cc/layers/layer.cc

// Copyright 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/layers/layer.h"

#include <algorithm>

#include "base/atomic_sequence_num.h"
#include "base/location.h"
#include "base/metrics/histogram.h"
#include "base/single_thread_task_runner.h"
#include "base/time/time.h"
#include "base/trace_event/trace_event.h"
#include "cc/animation/animation.h"
#include "cc/animation/animation_events.h"
#include "cc/animation/animation_registrar.h"
#include "cc/animation/keyframed_animation_curve.h"
#include "cc/animation/layer_animation_controller.h"
#include "cc/base/simple_enclosed_region.h"
#include "cc/layers/layer_client.h"
#include "cc/layers/layer_impl.h"
#include "cc/layers/scrollbar_layer_interface.h"
#include "cc/output/copy_output_request.h"
#include "cc/output/copy_output_result.h"
#include "cc/trees/layer_tree_host.h"
#include "cc/trees/layer_tree_impl.h"
#include "third_party/skia/include/core/SkImageFilter.h"
#include "ui/gfx/geometry/rect_conversions.h"
#include "ui/gfx/geometry/vector2d_conversions.h"

namespace cc {

base::StaticAtomicSequenceNumber g_next_layer_id;

scoped_refptr<Layer> Layer::Create() {
  return make_scoped_refptr(new Layer());
}

Layer::Layer()
    : needs_push_properties_(false),
      num_dependents_need_push_properties_(false),
      stacking_order_changed_(false),
      // Layer IDs start from 1.
      layer_id_(g_next_layer_id.GetNext() + 1),
      ignore_set_needs_commit_(false),
      sorting_context_id_(0),
      parent_(nullptr),
      layer_tree_host_(nullptr),
      scroll_clip_layer_id_(INVALID_ID),
      num_descendants_that_draw_content_(0),
      transform_tree_index_(-1),
      opacity_tree_index_(-1),
      clip_tree_index_(-1),
      should_flatten_transform_from_property_tree_(false),
      should_scroll_on_main_thread_(false),
      have_wheel_event_handlers_(false),
      have_scroll_event_handlers_(false),
      user_scrollable_horizontal_(true),
      user_scrollable_vertical_(true),
      is_root_for_isolated_group_(false),
      is_container_for_fixed_position_layers_(false),
      is_drawable_(false),
      draws_content_(false),
      hide_layer_and_subtree_(false),
      masks_to_bounds_(false),
      contents_opaque_(false),
      double_sided_(true),
      should_flatten_transform_(true),
      use_parent_backface_visibility_(false),
      draw_checkerboard_for_missing_tiles_(false),
      force_render_surface_(false),
      transform_is_invertible_(true),
      has_render_surface_(false),
      scroll_blocks_on_(SCROLL_BLOCKS_ON_NONE),
      background_color_(0),
      opacity_(1.f),
      blend_mode_(SkXfermode::kSrcOver_Mode),
      scroll_parent_(nullptr),
      clip_parent_(nullptr),
      replica_layer_(nullptr),
      raster_scale_(0.f),
      client_(nullptr),
      frame_timing_requests_dirty_(false) {
  layer_animation_controller_ = LayerAnimationController::Create(layer_id_);
  layer_animation_controller_->AddValueObserver(this);
  layer_animation_controller_->set_value_provider(this);
}

Layer::~Layer() {
  // Our parent should be holding a reference to us so there should be no
  // way for us to be destroyed while we still have a parent.
  DCHECK(!parent());
  // Similarly we shouldn't have a layer tree host since it also keeps a
  // reference to us.
  DCHECK(!layer_tree_host());

  layer_animation_controller_->RemoveValueObserver(this);
  layer_animation_controller_->remove_value_provider(this);

  RemoveFromScrollTree();
  RemoveFromClipTree();

  // Remove the parent reference from all children and dependents.
  RemoveAllChildren();
  if (mask_layer_.get()) {
    DCHECK_EQ(this, mask_layer_->parent());
    mask_layer_->RemoveFromParent();
  }
  if (replica_layer_.get()) {
    DCHECK_EQ(this, replica_layer_->parent());
    replica_layer_->RemoveFromParent();
  }
}

void Layer::SetLayerTreeHost(LayerTreeHost* host) {
  if (layer_tree_host_ == host)
    return;

  layer_tree_host_ = host;

  // When changing hosts, the layer needs to commit its properties to the impl
  // side for the new host.
  SetNeedsPushProperties();

  for (size_t i = 0; i < children_.size(); ++i)
    children_[i]->SetLayerTreeHost(host);

  if (mask_layer_.get())
    mask_layer_->SetLayerTreeHost(host);
  if (replica_layer_.get())
    replica_layer_->SetLayerTreeHost(host);

  if (host) {
    layer_animation_controller_->SetAnimationRegistrar(
        host->animation_registrar());

    if (host->settings().layer_transforms_should_scale_layer_contents)
      reset_raster_scale_to_unknown();
  }

  if (host && layer_animation_controller_->has_any_animation())
    host->SetNeedsCommit();
}

void Layer::SetNeedsUpdate() {
  if (layer_tree_host_ && !ignore_set_needs_commit_)
    layer_tree_host_->SetNeedsUpdateLayers();
}

void Layer::SetNeedsCommit() {
  if (!layer_tree_host_)
    return;

  SetNeedsPushProperties();

  if (ignore_set_needs_commit_)
    return;

  layer_tree_host_->SetNeedsCommit();
}

void Layer::SetNeedsFullTreeSync() {
  if (!layer_tree_host_)
    return;

  layer_tree_host_->SetNeedsFullTreeSync();
}

void Layer::SetNextCommitWaitsForActivation() {
  if (!layer_tree_host_)
    return;

  layer_tree_host_->SetNextCommitWaitsForActivation();
}

void Layer::SetNeedsPushProperties() {
  if (needs_push_properties_)
    return;
  if (!parent_should_know_need_push_properties() && parent_)
    parent_->AddDependentNeedsPushProperties();
  needs_push_properties_ = true;
}

void Layer::AddDependentNeedsPushProperties() {
  DCHECK_GE(num_dependents_need_push_properties_, 0);

  if (!parent_should_know_need_push_properties() && parent_)
    parent_->AddDependentNeedsPushProperties();

  num_dependents_need_push_properties_++;
}

void Layer::RemoveDependentNeedsPushProperties() {
  num_dependents_need_push_properties_--;
  DCHECK_GE(num_dependents_need_push_properties_, 0);

  if (!parent_should_know_need_push_properties() && parent_)
      parent_->RemoveDependentNeedsPushProperties();
}

bool Layer::IsPropertyChangeAllowed() const {
  if (!layer_tree_host_)
    return true;

  if (!layer_tree_host_->settings().strict_layer_property_change_checking)
    return true;

  return !layer_tree_host_->in_paint_layer_contents();
}

gfx::Rect Layer::LayerRectToContentRect(const gfx::Rect& layer_rect) const {
  gfx::Rect content_rect = gfx::ScaleToEnclosingRect(
      layer_rect, contents_scale_x(), contents_scale_y());
  // Intersect with content rect to avoid the extra pixel because for some
  // values x and y, ceil((x / y) * y) may be x + 1.
  content_rect.Intersect(gfx::Rect(content_bounds()));
  return content_rect;
}

skia::RefPtr<SkPicture> Layer::GetPicture() const {
  return skia::RefPtr<SkPicture>();
}

void Layer::SetParent(Layer* layer) {
  DCHECK(!layer || !layer->HasAncestor(this));

  if (parent_should_know_need_push_properties()) {
    if (parent_)
      parent_->RemoveDependentNeedsPushProperties();
    if (layer)
      layer->AddDependentNeedsPushProperties();
  }

  parent_ = layer;
  SetLayerTreeHost(parent_ ? parent_->layer_tree_host() : nullptr);

  if (!layer_tree_host_)
    return;
  const LayerTreeSettings& settings = layer_tree_host_->settings();
  if (!settings.layer_transforms_should_scale_layer_contents)
    return;

  reset_raster_scale_to_unknown();
  if (mask_layer_.get())
    mask_layer_->reset_raster_scale_to_unknown();
  if (replica_layer_.get() && replica_layer_->mask_layer_.get())
    replica_layer_->mask_layer_->reset_raster_scale_to_unknown();
}

void Layer::AddChild(scoped_refptr<Layer> child) {
  InsertChild(child, children_.size());
}

void Layer::InsertChild(scoped_refptr<Layer> child, size_t index) {
  DCHECK(IsPropertyChangeAllowed());
  child->RemoveFromParent();
  AddDrawableDescendants(child->NumDescendantsThatDrawContent() +
                         (child->DrawsContent() ? 1 : 0));
  child->SetParent(this);
  child->stacking_order_changed_ = true;

  index = std::min(index, children_.size());
  children_.insert(children_.begin() + index, child);
  SetNeedsFullTreeSync();
}

void Layer::RemoveFromParent() {
  DCHECK(IsPropertyChangeAllowed());
  if (parent_)
    parent_->RemoveChildOrDependent(this);
}

void Layer::RemoveChildOrDependent(Layer* child) {
  if (mask_layer_.get() == child) {
    mask_layer_->SetParent(nullptr);
    mask_layer_ = nullptr;
    SetNeedsFullTreeSync();
    return;
  }
  if (replica_layer_.get() == child) {
    replica_layer_->SetParent(nullptr);
    replica_layer_ = nullptr;
    SetNeedsFullTreeSync();
    return;
  }

  for (LayerList::iterator iter = children_.begin();
       iter != children_.end();
       ++iter) {
    if (iter->get() != child)
      continue;

    child->SetParent(nullptr);
    AddDrawableDescendants(-child->NumDescendantsThatDrawContent() -
                           (child->DrawsContent() ? 1 : 0));
    children_.erase(iter);
    SetNeedsFullTreeSync();
    return;
  }
}

void Layer::ReplaceChild(Layer* reference, scoped_refptr<Layer> new_layer) {
  DCHECK(reference);
  DCHECK_EQ(reference->parent(), this);
  DCHECK(IsPropertyChangeAllowed());

  if (reference == new_layer.get())
    return;

  int reference_index = IndexOfChild(reference);
  if (reference_index == -1) {
    NOTREACHED();
    return;
  }

  reference->RemoveFromParent();

  if (new_layer.get()) {
    new_layer->RemoveFromParent();
    InsertChild(new_layer, reference_index);
  }
}

int Layer::IndexOfChild(const Layer* reference) {
  for (size_t i = 0; i < children_.size(); ++i) {
    if (children_[i].get() == reference)
      return i;
  }
  return -1;
}

void Layer::SetBounds(const gfx::Size& size) {
  DCHECK(IsPropertyChangeAllowed());
  if (bounds() == size)
    return;

  bounds_ = size;
  SetNeedsCommit();
}

Layer* Layer::RootLayer() {
  Layer* layer = this;
  while (layer->parent())
    layer = layer->parent();
  return layer;
}

void Layer::RemoveAllChildren() {
  DCHECK(IsPropertyChangeAllowed());
  while (children_.size()) {
    Layer* layer = children_[0].get();
    DCHECK_EQ(this, layer->parent());
    layer->RemoveFromParent();
  }
}

void Layer::SetChildren(const LayerList& children) {
  DCHECK(IsPropertyChangeAllowed());
  if (children == children_)
    return;

  RemoveAllChildren();
  for (size_t i = 0; i < children.size(); ++i)
    AddChild(children[i]);
}

bool Layer::HasAncestor(const Layer* ancestor) const {
  for (const Layer* layer = parent(); layer; layer = layer->parent()) {
    if (layer == ancestor)
      return true;
  }
  return false;
}

void Layer::RequestCopyOfOutput(
    scoped_ptr<CopyOutputRequest> request) {
  DCHECK(IsPropertyChangeAllowed());
  if (request->IsEmpty())
    return;
  copy_requests_.push_back(request.Pass());
  SetNeedsCommit();
}

void Layer::SetBackgroundColor(SkColor background_color) {
  DCHECK(IsPropertyChangeAllowed());
  if (background_color_ == background_color)
    return;
  background_color_ = background_color;
  SetNeedsCommit();
}

SkColor Layer::SafeOpaqueBackgroundColor() const {
  SkColor color = background_color();
  if (SkColorGetA(color) == 255 && !contents_opaque()) {
    color = SK_ColorTRANSPARENT;
  } else if (SkColorGetA(color) != 255 && contents_opaque()) {
    for (const Layer* layer = parent(); layer;
         layer = layer->parent()) {
      color = layer->background_color();
      if (SkColorGetA(color) == 255)
        break;
    }
    if (SkColorGetA(color) != 255)
      color = layer_tree_host_->background_color();
    if (SkColorGetA(color) != 255)
      color = SkColorSetA(color, 255);
  }
  return color;
}

void Layer::CalculateContentsScale(float ideal_contents_scale,
                                   float* contents_scale_x,
                                   float* contents_scale_y,
                                   gfx::Size* content_bounds) {
  DCHECK(layer_tree_host_);

  *contents_scale_x = 1;
  *contents_scale_y = 1;
  *content_bounds = bounds();
}

void Layer::SetMasksToBounds(bool masks_to_bounds) {
  DCHECK(IsPropertyChangeAllowed());
  if (masks_to_bounds_ == masks_to_bounds)
    return;
  masks_to_bounds_ = masks_to_bounds;
  SetNeedsCommit();
}

void Layer::SetMaskLayer(Layer* mask_layer) {
  DCHECK(IsPropertyChangeAllowed());
  if (mask_layer_.get() == mask_layer)
    return;
  if (mask_layer_.get()) {
    DCHECK_EQ(this, mask_layer_->parent());
    mask_layer_->RemoveFromParent();
  }
  mask_layer_ = mask_layer;
  if (mask_layer_.get()) {
    DCHECK(!mask_layer_->parent());
    mask_layer_->RemoveFromParent();
    mask_layer_->SetParent(this);
    mask_layer_->SetIsMask(true);
  }
  SetNeedsFullTreeSync();
}

void Layer::SetReplicaLayer(Layer* layer) {
  DCHECK(IsPropertyChangeAllowed());
  if (replica_layer_.get() == layer)
    return;
  if (replica_layer_.get()) {
    DCHECK_EQ(this, replica_layer_->parent());
    replica_layer_->RemoveFromParent();
  }
  replica_layer_ = layer;
  if (replica_layer_.get()) {
    DCHECK(!replica_layer_->parent());
    replica_layer_->RemoveFromParent();
    replica_layer_->SetParent(this);
  }
  SetNeedsFullTreeSync();
}

void Layer::SetFilters(const FilterOperations& filters) {
  DCHECK(IsPropertyChangeAllowed());
  if (filters_ == filters)
    return;
  filters_ = filters;
  SetNeedsCommit();
}

bool Layer::FilterIsAnimating() const {
  return layer_animation_controller_->IsAnimatingProperty(Animation::FILTER);
}

void Layer::SetBackgroundFilters(const FilterOperations& filters) {
  DCHECK(IsPropertyChangeAllowed());
  if (background_filters_ == filters)
    return;
  background_filters_ = filters;
  SetNeedsCommit();
}

void Layer::SetOpacity(float opacity) {
  DCHECK(IsPropertyChangeAllowed());
  if (opacity_ == opacity)
    return;
  opacity_ = opacity;
  SetNeedsCommit();
}

bool Layer::OpacityIsAnimating() const {
  return layer_animation_controller_->IsAnimatingProperty(Animation::OPACITY);
}

bool Layer::OpacityCanAnimateOnImplThread() const {
  return false;
}

void Layer::SetBlendMode(SkXfermode::Mode blend_mode) {
  DCHECK(IsPropertyChangeAllowed());
  if (blend_mode_ == blend_mode)
    return;

  // Allowing only blend modes that are defined in the CSS Compositing standard:
  // http://dev.w3.org/fxtf/compositing-1/#blending
  switch (blend_mode) {
    case SkXfermode::kSrcOver_Mode:
    case SkXfermode::kScreen_Mode:
    case SkXfermode::kOverlay_Mode:
    case SkXfermode::kDarken_Mode:
    case SkXfermode::kLighten_Mode:
    case SkXfermode::kColorDodge_Mode:
    case SkXfermode::kColorBurn_Mode:
    case SkXfermode::kHardLight_Mode:
    case SkXfermode::kSoftLight_Mode:
    case SkXfermode::kDifference_Mode:
    case SkXfermode::kExclusion_Mode:
    case SkXfermode::kMultiply_Mode:
    case SkXfermode::kHue_Mode:
    case SkXfermode::kSaturation_Mode:
    case SkXfermode::kColor_Mode:
    case SkXfermode::kLuminosity_Mode:
      // supported blend modes
      break;
    case SkXfermode::kClear_Mode:
    case SkXfermode::kSrc_Mode:
    case SkXfermode::kDst_Mode:
    case SkXfermode::kDstOver_Mode:
    case SkXfermode::kSrcIn_Mode:
    case SkXfermode::kDstIn_Mode:
    case SkXfermode::kSrcOut_Mode:
    case SkXfermode::kDstOut_Mode:
    case SkXfermode::kSrcATop_Mode:
    case SkXfermode::kDstATop_Mode:
    case SkXfermode::kXor_Mode:
    case SkXfermode::kPlus_Mode:
    case SkXfermode::kModulate_Mode:
      // Porter Duff Compositing Operators are not yet supported
      // http://dev.w3.org/fxtf/compositing-1/#porterduffcompositingoperators
      NOTREACHED();
      return;
  }

  blend_mode_ = blend_mode;
  SetNeedsCommit();
}

void Layer::SetIsRootForIsolatedGroup(bool root) {
  DCHECK(IsPropertyChangeAllowed());
  if (is_root_for_isolated_group_ == root)
    return;
  is_root_for_isolated_group_ = root;
  SetNeedsCommit();
}

void Layer::SetContentsOpaque(bool opaque) {
  DCHECK(IsPropertyChangeAllowed());
  if (contents_opaque_ == opaque)
    return;
  contents_opaque_ = opaque;
  SetNeedsCommit();
}

void Layer::SetPosition(const gfx::PointF& position) {
  DCHECK(IsPropertyChangeAllowed());
  if (position_ == position)
    return;
  position_ = position;
  SetNeedsCommit();
}

bool Layer::IsContainerForFixedPositionLayers() const {
  if (!transform_.IsIdentityOrTranslation())
    return true;
  if (parent_ && !parent_->transform_.IsIdentityOrTranslation())
    return true;
  return is_container_for_fixed_position_layers_;
}

void Layer::SetTransform(const gfx::Transform& transform) {
  DCHECK(IsPropertyChangeAllowed());
  if (transform_ == transform)
    return;
  transform_ = transform;
  transform_is_invertible_ = transform.IsInvertible();
  SetNeedsCommit();
}

void Layer::SetTransformOrigin(const gfx::Point3F& transform_origin) {
  DCHECK(IsPropertyChangeAllowed());
  if (transform_origin_ == transform_origin)
    return;
  transform_origin_ = transform_origin;
  SetNeedsCommit();
}

bool Layer::AnimationsPreserveAxisAlignment() const {
  return layer_animation_controller_->AnimationsPreserveAxisAlignment();
}

bool Layer::TransformIsAnimating() const {
  return layer_animation_controller_->IsAnimatingProperty(Animation::TRANSFORM);
}

void Layer::SetScrollParent(Layer* parent) {
  DCHECK(IsPropertyChangeAllowed());
  if (scroll_parent_ == parent)
    return;

  if (scroll_parent_)
    scroll_parent_->RemoveScrollChild(this);

  scroll_parent_ = parent;

  if (scroll_parent_)
    scroll_parent_->AddScrollChild(this);

  SetNeedsCommit();
}

void Layer::AddScrollChild(Layer* child) {
  if (!scroll_children_)
    scroll_children_.reset(new std::set<Layer*>);
  scroll_children_->insert(child);
  SetNeedsCommit();
}

void Layer::RemoveScrollChild(Layer* child) {
  scroll_children_->erase(child);
  if (scroll_children_->empty())
    scroll_children_ = nullptr;
  SetNeedsCommit();
}

void Layer::SetClipParent(Layer* ancestor) {
  DCHECK(IsPropertyChangeAllowed());
  if (clip_parent_ == ancestor)
    return;

  if (clip_parent_)
    clip_parent_->RemoveClipChild(this);

  clip_parent_ = ancestor;

  if (clip_parent_)
    clip_parent_->AddClipChild(this);

  SetNeedsCommit();
}

void Layer::AddClipChild(Layer* child) {
  if (!clip_children_)
    clip_children_.reset(new std::set<Layer*>);
  clip_children_->insert(child);
  SetNeedsCommit();
}

void Layer::RemoveClipChild(Layer* child) {
  clip_children_->erase(child);
  if (clip_children_->empty())
    clip_children_ = nullptr;
  SetNeedsCommit();
}

void Layer::SetScrollOffset(const gfx::ScrollOffset& scroll_offset) {
  DCHECK(IsPropertyChangeAllowed());

  if (scroll_offset_ == scroll_offset)
    return;
  scroll_offset_ = scroll_offset;
  SetNeedsCommit();
}

void Layer::SetScrollCompensationAdjustment(
    const gfx::Vector2dF& scroll_compensation_adjustment) {
  if (scroll_compensation_adjustment_ == scroll_compensation_adjustment)
    return;
  scroll_compensation_adjustment_ = scroll_compensation_adjustment;
  SetNeedsCommit();
}

gfx::Vector2dF Layer::ScrollCompensationAdjustment() const {
  return scroll_compensation_adjustment_;
}

void Layer::SetScrollOffsetFromImplSide(
    const gfx::ScrollOffset& scroll_offset) {
  DCHECK(IsPropertyChangeAllowed());
  // This function only gets called during a BeginMainFrame, so there
  // is no need to call SetNeedsUpdate here.
  DCHECK(layer_tree_host_ && layer_tree_host_->CommitRequested());
  if (scroll_offset_ == scroll_offset)
    return;
  scroll_offset_ = scroll_offset;
  SetNeedsPushProperties();
  if (!did_scroll_callback_.is_null())
    did_scroll_callback_.Run();
  // The callback could potentially change the layer structure:
  // "this" may have been destroyed during the process.
}

void Layer::SetScrollClipLayerId(int clip_layer_id) {
  DCHECK(IsPropertyChangeAllowed());
  if (scroll_clip_layer_id_ == clip_layer_id)
    return;
  scroll_clip_layer_id_ = clip_layer_id;
  SetNeedsCommit();
}

void Layer::SetUserScrollable(bool horizontal, bool vertical) {
  DCHECK(IsPropertyChangeAllowed());
  if (user_scrollable_horizontal_ == horizontal &&
      user_scrollable_vertical_ == vertical)
    return;
  user_scrollable_horizontal_ = horizontal;
  user_scrollable_vertical_ = vertical;
  SetNeedsCommit();
}

void Layer::SetShouldScrollOnMainThread(bool should_scroll_on_main_thread) {
  DCHECK(IsPropertyChangeAllowed());
  if (should_scroll_on_main_thread_ == should_scroll_on_main_thread)
    return;
  should_scroll_on_main_thread_ = should_scroll_on_main_thread;
  SetNeedsCommit();
}

void Layer::SetHaveWheelEventHandlers(bool have_wheel_event_handlers) {
  DCHECK(IsPropertyChangeAllowed());
  if (have_wheel_event_handlers_ == have_wheel_event_handlers)
    return;
  have_wheel_event_handlers_ = have_wheel_event_handlers;
  SetNeedsCommit();
}

void Layer::SetHaveScrollEventHandlers(bool have_scroll_event_handlers) {
  DCHECK(IsPropertyChangeAllowed());
  if (have_scroll_event_handlers_ == have_scroll_event_handlers)
    return;
  have_scroll_event_handlers_ = have_scroll_event_handlers;
  SetNeedsCommit();
}

void Layer::SetNonFastScrollableRegion(const Region& region) {
  DCHECK(IsPropertyChangeAllowed());
  if (non_fast_scrollable_region_ == region)
    return;
  non_fast_scrollable_region_ = region;
  SetNeedsCommit();
}

void Layer::SetTouchEventHandlerRegion(const Region& region) {
  DCHECK(IsPropertyChangeAllowed());
  if (touch_event_handler_region_ == region)
    return;
  touch_event_handler_region_ = region;
  SetNeedsCommit();
}

void Layer::SetScrollBlocksOn(ScrollBlocksOn scroll_blocks_on) {
  DCHECK(IsPropertyChangeAllowed());
  if (scroll_blocks_on_ == scroll_blocks_on)
    return;
  scroll_blocks_on_ = scroll_blocks_on;
  SetNeedsCommit();
}

void Layer::SetDrawCheckerboardForMissingTiles(bool checkerboard) {
  DCHECK(IsPropertyChangeAllowed());
  if (draw_checkerboard_for_missing_tiles_ == checkerboard)
    return;
  draw_checkerboard_for_missing_tiles_ = checkerboard;
  SetNeedsCommit();
}

void Layer::SetForceRenderSurface(bool force) {
  DCHECK(IsPropertyChangeAllowed());
  if (force_render_surface_ == force)
    return;
  force_render_surface_ = force;
  SetNeedsCommit();
}

void Layer::SetDoubleSided(bool double_sided) {
  DCHECK(IsPropertyChangeAllowed());
  if (double_sided_ == double_sided)
    return;
  double_sided_ = double_sided;
  SetNeedsCommit();
}

void Layer::Set3dSortingContextId(int id) {
  DCHECK(IsPropertyChangeAllowed());
  if (id == sorting_context_id_)
    return;
  sorting_context_id_ = id;
  SetNeedsCommit();
}

void Layer::SetShouldFlattenTransform(bool should_flatten) {
  DCHECK(IsPropertyChangeAllowed());
  if (should_flatten_transform_ == should_flatten)
    return;
  should_flatten_transform_ = should_flatten;
  SetNeedsCommit();
}

void Layer::SetIsDrawable(bool is_drawable) {
  DCHECK(IsPropertyChangeAllowed());
  if (is_drawable_ == is_drawable)
    return;

  is_drawable_ = is_drawable;
  UpdateDrawsContent(HasDrawableContent());
}

void Layer::SetHideLayerAndSubtree(bool hide) {
  DCHECK(IsPropertyChangeAllowed());
  if (hide_layer_and_subtree_ == hide)
    return;

  hide_layer_and_subtree_ = hide;
  SetNeedsCommit();
}

void Layer::SetNeedsDisplayRect(const gfx::Rect& dirty_rect) {
  if (dirty_rect.IsEmpty())
    return;

  SetNeedsPushProperties();
  update_rect_.Union(dirty_rect);

  if (DrawsContent())
    SetNeedsUpdate();
}

bool Layer::DescendantIsFixedToContainerLayer() const {
  for (size_t i = 0; i < children_.size(); ++i) {
    if (children_[i]->position_constraint_.is_fixed_position() ||
        children_[i]->DescendantIsFixedToContainerLayer())
      return true;
  }
  return false;
}

void Layer::SetIsContainerForFixedPositionLayers(bool container) {
  if (is_container_for_fixed_position_layers_ == container)
    return;
  is_container_for_fixed_position_layers_ = container;

  if (layer_tree_host_ && layer_tree_host_->CommitRequested())
    return;

  // Only request a commit if we have a fixed positioned descendant.
  if (DescendantIsFixedToContainerLayer())
    SetNeedsCommit();
}

void Layer::SetPositionConstraint(const LayerPositionConstraint& constraint) {
  DCHECK(IsPropertyChangeAllowed());
  if (position_constraint_ == constraint)
    return;
  position_constraint_ = constraint;
  SetNeedsCommit();
}

static void RunCopyCallbackOnMainThread(scoped_ptr<CopyOutputRequest> request,
                                        scoped_ptr<CopyOutputResult> result) {
  request->SendResult(result.Pass());
}

static void PostCopyCallbackToMainThread(
    scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner,
    scoped_ptr<CopyOutputRequest> request,
    scoped_ptr<CopyOutputResult> result) {
  main_thread_task_runner->PostTask(FROM_HERE,
                                    base::Bind(&RunCopyCallbackOnMainThread,
                                               base::Passed(&request),
                                               base::Passed(&result)));
}

void Layer::PushPropertiesTo(LayerImpl* layer) {
  DCHECK(layer_tree_host_);

  // If we did not SavePaintProperties() for the layer this frame, then push the
  // real property values, not the paint property values.
  bool use_paint_properties = paint_properties_.source_frame_number ==
                              layer_tree_host_->source_frame_number();

  layer->SetTransformOrigin(transform_origin_);
  layer->SetBackgroundColor(background_color_);
  layer->SetBounds(use_paint_properties ? paint_properties_.bounds
                                        : bounds_);
  layer->SetContentBounds(content_bounds());
  layer->SetContentsScale(contents_scale_x(), contents_scale_y());

  bool is_tracing;
  TRACE_EVENT_CATEGORY_GROUP_ENABLED(
      TRACE_DISABLED_BY_DEFAULT("cc.debug") "," TRACE_DISABLED_BY_DEFAULT(
          "devtools.timeline.layers"),
      &is_tracing);
  if (is_tracing)
    layer->SetDebugInfo(TakeDebugInfo());

  layer->SetDoubleSided(double_sided_);
  layer->SetDrawCheckerboardForMissingTiles(
      draw_checkerboard_for_missing_tiles_);
  layer->SetDrawsContent(DrawsContent());
  layer->SetHideLayerAndSubtree(hide_layer_and_subtree_);
  layer->SetHasRenderSurface(has_render_surface_ || layer->HasCopyRequest());
  if (!layer->FilterIsAnimatingOnImplOnly() && !FilterIsAnimating())
    layer->SetFilters(filters_);
  DCHECK(!(FilterIsAnimating() && layer->FilterIsAnimatingOnImplOnly()));
  layer->SetBackgroundFilters(background_filters());
  layer->SetMasksToBounds(masks_to_bounds_);
  layer->SetShouldScrollOnMainThread(should_scroll_on_main_thread_);
  layer->SetHaveWheelEventHandlers(have_wheel_event_handlers_);
  layer->SetHaveScrollEventHandlers(have_scroll_event_handlers_);
  layer->SetNonFastScrollableRegion(non_fast_scrollable_region_);
  layer->SetTouchEventHandlerRegion(touch_event_handler_region_);
  layer->SetScrollBlocksOn(scroll_blocks_on_);
  layer->SetContentsOpaque(contents_opaque_);
  if (!layer->OpacityIsAnimatingOnImplOnly() && !OpacityIsAnimating())
    layer->SetOpacity(opacity_);
  DCHECK(!(OpacityIsAnimating() && layer->OpacityIsAnimatingOnImplOnly()));
  layer->SetBlendMode(blend_mode_);
  layer->SetIsRootForIsolatedGroup(is_root_for_isolated_group_);
  layer->SetPosition(position_);
  layer->SetIsContainerForFixedPositionLayers(
      IsContainerForFixedPositionLayers());
  layer->SetPositionConstraint(position_constraint_);
  layer->SetShouldFlattenTransform(should_flatten_transform_);
  layer->SetUseParentBackfaceVisibility(use_parent_backface_visibility_);
  if (!layer->TransformIsAnimatingOnImplOnly() && !TransformIsAnimating())
    layer->SetTransformAndInvertibility(transform_, transform_is_invertible_);
  DCHECK(!(TransformIsAnimating() && layer->TransformIsAnimatingOnImplOnly()));
  layer->Set3dSortingContextId(sorting_context_id_);
  layer->SetNumDescendantsThatDrawContent(num_descendants_that_draw_content_);

  layer->SetScrollClipLayer(scroll_clip_layer_id_);
  layer->set_user_scrollable_horizontal(user_scrollable_horizontal_);
  layer->set_user_scrollable_vertical(user_scrollable_vertical_);

  LayerImpl* scroll_parent = nullptr;
  if (scroll_parent_) {
    scroll_parent = layer->layer_tree_impl()->LayerById(scroll_parent_->id());
    DCHECK(scroll_parent);
  }

  layer->SetScrollParent(scroll_parent);
  if (scroll_children_) {
    std::set<LayerImpl*>* scroll_children = new std::set<LayerImpl*>;
    for (std::set<Layer*>::iterator it = scroll_children_->begin();
         it != scroll_children_->end();
         ++it) {
      DCHECK_EQ((*it)->scroll_parent(), this);
      LayerImpl* scroll_child =
          layer->layer_tree_impl()->LayerById((*it)->id());
      DCHECK(scroll_child);
      scroll_children->insert(scroll_child);
    }
    layer->SetScrollChildren(scroll_children);
  } else {
    layer->SetScrollChildren(nullptr);
  }

  LayerImpl* clip_parent = nullptr;
  if (clip_parent_) {
    clip_parent =
        layer->layer_tree_impl()->LayerById(clip_parent_->id());
    DCHECK(clip_parent);
  }

  layer->SetClipParent(clip_parent);
  if (clip_children_) {
    std::set<LayerImpl*>* clip_children = new std::set<LayerImpl*>;
    for (std::set<Layer*>::iterator it = clip_children_->begin();
        it != clip_children_->end(); ++it) {
      DCHECK_EQ((*it)->clip_parent(), this);
      LayerImpl* clip_child = layer->layer_tree_impl()->LayerById((*it)->id());
      DCHECK(clip_child);
      clip_children->insert(clip_child);
    }
    layer->SetClipChildren(clip_children);
  } else {
    layer->SetClipChildren(nullptr);
  }

  // When a scroll offset animation is interrupted the new scroll position on
  // the pending tree will clobber any impl-side scrolling occuring on the
  // active tree. To do so, avoid scrolling the pending tree along with it
  // instead of trying to undo that scrolling later.
  if (layer_animation_controller_->scroll_offset_animation_was_interrupted())
    layer->PushScrollOffsetFromMainThreadAndClobberActiveValue(scroll_offset_);
  else
    layer->PushScrollOffsetFromMainThread(scroll_offset_);
  layer->SetScrollCompensationAdjustment(ScrollCompensationAdjustment());

  // Wrap the copy_requests_ in a PostTask to the main thread.
  ScopedPtrVector<CopyOutputRequest> main_thread_copy_requests;
  for (ScopedPtrVector<CopyOutputRequest>::iterator it = copy_requests_.begin();
       it != copy_requests_.end();
       ++it) {
    scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner =
        layer_tree_host()->proxy()->MainThreadTaskRunner();
    scoped_ptr<CopyOutputRequest> original_request = copy_requests_.take(it);
    const CopyOutputRequest& original_request_ref = *original_request;
    scoped_ptr<CopyOutputRequest> main_thread_request =
        CopyOutputRequest::CreateRelayRequest(
            original_request_ref,
            base::Bind(&PostCopyCallbackToMainThread,
                       main_thread_task_runner,
                       base::Passed(&original_request)));
    main_thread_copy_requests.push_back(main_thread_request.Pass());
  }
  copy_requests_.clear();
  layer->PassCopyRequests(&main_thread_copy_requests);

  // If the main thread commits multiple times before the impl thread actually
  // draws, then damage tracking will become incorrect if we simply clobber the
  // update_rect here. The LayerImpl's update_rect needs to accumulate (i.e.
  // union) any update changes that have occurred on the main thread.
  update_rect_.Union(layer->update_rect());
  layer->SetUpdateRect(update_rect_);

  layer->SetStackingOrderChanged(stacking_order_changed_);

  layer_animation_controller_->PushAnimationUpdatesTo(
      layer->layer_animation_controller());

  if (frame_timing_requests_dirty_) {
    layer->PassFrameTimingRequests(&frame_timing_requests_);
    frame_timing_requests_dirty_ = false;
  }

  // Reset any state that should be cleared for the next update.
  stacking_order_changed_ = false;
  update_rect_ = gfx::Rect();

  needs_push_properties_ = false;
  num_dependents_need_push_properties_ = 0;
}

scoped_ptr<LayerImpl> Layer::CreateLayerImpl(LayerTreeImpl* tree_impl) {
  return LayerImpl::Create(tree_impl, layer_id_,
                           new LayerImpl::SyncedScrollOffset);
}

bool Layer::DrawsContent() const {
  return draws_content_;
}

bool Layer::HasDrawableContent() const {
  return is_drawable_;
}

void Layer::UpdateDrawsContent(bool has_drawable_content) {
  bool draws_content = has_drawable_content;
  DCHECK(is_drawable_ || !has_drawable_content);
  if (draws_content == draws_content_)
    return;

  if (HasDelegatedContent()) {
    // Layers with delegated content need to be treated as if they have as
    // many children as the number of layers they own delegated quads for.
    // Since we don't know this number right now, we choose one that acts like
    // infinity for our purposes.
    AddDrawableDescendants(draws_content ? 1000 : -1000);
  }

  if (parent())
    parent()->AddDrawableDescendants(draws_content ? 1 : -1);

  draws_content_ = draws_content;
  SetNeedsCommit();
}

int Layer::NumDescendantsThatDrawContent() const {
  return num_descendants_that_draw_content_;
}

void Layer::SavePaintProperties() {
  DCHECK(layer_tree_host_);

  // TODO(reveman): Save all layer properties that we depend on not
  // changing until PushProperties() has been called. crbug.com/231016
  paint_properties_.bounds = bounds_;
  paint_properties_.source_frame_number =
      layer_tree_host_->source_frame_number();
}

bool Layer::Update(ResourceUpdateQueue* queue,
                   const OcclusionTracker<Layer>* occlusion) {
  DCHECK(layer_tree_host_);
  DCHECK_EQ(layer_tree_host_->source_frame_number(),
            paint_properties_.source_frame_number) <<
      "SavePaintProperties must be called for any layer that is painted.";
  return false;
}

bool Layer::NeedMoreUpdates() {
  return false;
}

bool Layer::IsSuitableForGpuRasterization() const {
  return true;
}

scoped_refptr<base::trace_event::ConvertableToTraceFormat>
Layer::TakeDebugInfo() {
  if (client_)
    return client_->TakeDebugInfo();
  else
    return nullptr;
}

void Layer::SetHasRenderSurface(bool has_render_surface) {
  if (has_render_surface_ == has_render_surface)
    return;
  has_render_surface_ = has_render_surface;
  // We do not need SetNeedsCommit here, since this is only ever called
  // during a commit, from CalculateDrawProperties.
  SetNeedsPushProperties();
}

void Layer::CreateRenderSurface() {
  DCHECK(!render_surface_);
  render_surface_ = make_scoped_ptr(new RenderSurface(this));
}

void Layer::ClearRenderSurface() {
  render_surface_ = nullptr;
}

void Layer::ClearRenderSurfaceLayerList() {
  if (render_surface_)
    render_surface_->ClearLayerLists();
}

gfx::ScrollOffset Layer::ScrollOffsetForAnimation() const {
  return CurrentScrollOffset();
}

// On<Property>Animated is called due to an ongoing accelerated animation.
// Since this animation is also being run on the compositor thread, there
// is no need to request a commit to push this value over, so the value is
// set directly rather than by calling Set<Property>.
void Layer::OnFilterAnimated(const FilterOperations& filters) {
  filters_ = filters;
}

void Layer::OnOpacityAnimated(float opacity) {
  opacity_ = opacity;
}

void Layer::OnTransformAnimated(const gfx::Transform& transform) {
  if (transform_ == transform)
    return;
  transform_ = transform;
  transform_is_invertible_ = transform.IsInvertible();
}

void Layer::OnScrollOffsetAnimated(const gfx::ScrollOffset& scroll_offset) {
  // Do nothing. Scroll deltas will be sent from the compositor thread back
  // to the main thread in the same manner as during non-animated
  // compositor-driven scrolling.
}

void Layer::OnAnimationWaitingForDeletion() {
  // Animations are only deleted during PushProperties.
  SetNeedsPushProperties();
}

bool Layer::IsActive() const {
  return true;
}

bool Layer::AddAnimation(scoped_ptr <Animation> animation) {
  if (!layer_animation_controller_->animation_registrar())
    return false;

  if (animation->target_property() == Animation::SCROLL_OFFSET &&
      !layer_animation_controller_->animation_registrar()
           ->supports_scroll_animations())
    return false;

  UMA_HISTOGRAM_BOOLEAN("Renderer.AnimationAddedToOrphanLayer",
                        !layer_tree_host_);
  layer_animation_controller_->AddAnimation(animation.Pass());
  SetNeedsCommit();
  return true;
}

void Layer::PauseAnimation(int animation_id, double time_offset) {
  layer_animation_controller_->PauseAnimation(
      animation_id, base::TimeDelta::FromSecondsD(time_offset));
  SetNeedsCommit();
}

void Layer::RemoveAnimation(int animation_id) {
  layer_animation_controller_->RemoveAnimation(animation_id);
  SetNeedsCommit();
}

void Layer::RemoveAnimation(int animation_id,
                            Animation::TargetProperty property) {
  layer_animation_controller_->RemoveAnimation(animation_id, property);
  SetNeedsCommit();
}

void Layer::SetLayerAnimationControllerForTest(
    scoped_refptr<LayerAnimationController> controller) {
  layer_animation_controller_->RemoveValueObserver(this);
  layer_animation_controller_ = controller;
  layer_animation_controller_->AddValueObserver(this);
  SetNeedsCommit();
}

bool Layer::HasActiveAnimation() const {
  return layer_animation_controller_->HasActiveAnimation();
}

void Layer::AddLayerAnimationEventObserver(
    LayerAnimationEventObserver* animation_observer) {
  layer_animation_controller_->AddEventObserver(animation_observer);
}

void Layer::RemoveLayerAnimationEventObserver(
    LayerAnimationEventObserver* animation_observer) {
  layer_animation_controller_->RemoveEventObserver(animation_observer);
}

SimpleEnclosedRegion Layer::VisibleContentOpaqueRegion() const {
  if (contents_opaque())
    return SimpleEnclosedRegion(visible_content_rect());
  return SimpleEnclosedRegion();
}

ScrollbarLayerInterface* Layer::ToScrollbarLayer() {
  return nullptr;
}

RenderingStatsInstrumentation* Layer::rendering_stats_instrumentation() const {
  return layer_tree_host_->rendering_stats_instrumentation();
}

void Layer::RemoveFromScrollTree() {
  if (scroll_children_.get()) {
    std::set<Layer*> copy = *scroll_children_;
    for (std::set<Layer*>::iterator it = copy.begin(); it != copy.end(); ++it)
      (*it)->SetScrollParent(nullptr);
  }

  DCHECK(!scroll_children_);
  SetScrollParent(nullptr);
}

void Layer::RemoveFromClipTree() {
  if (clip_children_.get()) {
    std::set<Layer*> copy = *clip_children_;
    for (std::set<Layer*>::iterator it = copy.begin(); it != copy.end(); ++it)
      (*it)->SetClipParent(nullptr);
  }

  DCHECK(!clip_children_);
  SetClipParent(nullptr);
}

void Layer::AddDrawableDescendants(int num) {
  DCHECK_GE(num_descendants_that_draw_content_, 0);
  DCHECK_GE(num_descendants_that_draw_content_ + num, 0);
  if (num == 0)
    return;
  num_descendants_that_draw_content_ += num;
  SetNeedsCommit();
  if (parent())
    parent()->AddDrawableDescendants(num);
}

void Layer::RunMicroBenchmark(MicroBenchmark* benchmark) {
  benchmark->RunOnLayer(this);
}

bool Layer::HasDelegatedContent() const {
  return false;
}

gfx::Transform Layer::screen_space_transform_from_property_trees(
    const TransformTree& tree) const {
  gfx::Transform xform(1, 0, 0, 1, offset_to_transform_parent().x(),
                       offset_to_transform_parent().y());
  if (transform_tree_index() >= 0) {
    gfx::Transform ssxform = tree.Node(transform_tree_index())->data.to_screen;
    xform.ConcatTransform(ssxform);
    if (should_flatten_transform_from_property_tree_)
      xform.FlattenTo2d();
  }
  xform.Scale(1.0 / contents_scale_x(), 1.0 / contents_scale_y());
  return xform;
}

gfx::Transform Layer::draw_transform_from_property_trees(
    const TransformTree& tree) const {
  const TransformNode* node = tree.Node(transform_tree_index());
  // TODO(vollick): ultimately we'll need to find this information (whether or
  // not we establish a render surface) somewhere other than the layer.
  const TransformNode* target_node =
      has_render_surface_ ? node : tree.Node(node->data.content_target_id);

  gfx::Transform xform;
  const bool owns_non_root_surface = parent() && render_surface();
  if (!owns_non_root_surface) {
    // If you're not the root, or you don't own a surface, you need to apply
    // your local offset.
    xform = node->data.to_target;
    if (should_flatten_transform_from_property_tree_)
      xform.FlattenTo2d();
    xform.Translate(offset_to_transform_parent().x(),
                    offset_to_transform_parent().y());
  } else {
    // Surfaces need to apply their sublayer scale.
    xform.Scale(target_node->data.sublayer_scale.x(),
                target_node->data.sublayer_scale.y());
  }
  xform.Scale(1.0 / contents_scale_x(), 1.0 / contents_scale_y());
  return xform;
}

float Layer::DrawOpacityFromPropertyTrees(const OpacityTree& tree) const {
  if (!render_target())
    return 0.f;

  const OpacityNode* target_node =
      tree.Node(render_target()->opacity_tree_index());
  const OpacityNode* node = tree.Node(opacity_tree_index());
  if (node == target_node)
    return 1.f;

  float draw_opacity = 1.f;
  while (node != target_node) {
    draw_opacity *= node->data;
    node = tree.parent(node);
  }
  return draw_opacity;
}

void Layer::SetFrameTimingRequests(
    const std::vector<FrameTimingRequest>& requests) {
  frame_timing_requests_ = requests;
  frame_timing_requests_dirty_ = true;
  SetNeedsCommit();
}

}  // namespace cc