diff --git a/DEPS b/DEPS
index 4264862..1016b6b 100644
--- a/DEPS
+++ b/DEPS
@@ -21,7 +21,7 @@
   'chromium_git': 'https://chromium.googlesource.com',
   'skia_revision': 'db284c52e62e8d16708e2065495a3b693b238771',
   'v8_revision': '3f036fc0ba4ca4483fe77822f8605c277d37ee24',
-  'base_revision': 'f613c71b2ed7fe4b4eff33fb7fd3b53e640b4359',
+  'base_revision': '163fb42027bea947916ba4d2fa03aa0ed7c3f99e',
   'angle_revision': '46ccef1992a8ede16a596c3dd73cff13c047267d',
   'buildtools_revision': '222bd42ce39d1bd8f08fe089b066f49c469e1cdf',
   'dart_revision': 'e4db01fdd43f019988a901eb51c72790652760a4',
diff --git a/ui/events/event_switches.cc b/ui/events/event_switches.cc
index dcc0014..a17fd8e 100644
--- a/ui/events/event_switches.cc
+++ b/ui/events/event_switches.cc
@@ -43,4 +43,9 @@
 const char kTouchCalibration[] = "touch-calibration";
 #endif
 
+#if defined(USE_X11)
+// Dispatch one event per iteration of the message loop.
+const char kDispatchOneEventPerLoop[] = "dispatch-one-event-per-loop";
+#endif
+
 }  // namespace switches
diff --git a/ui/events/event_switches.h b/ui/events/event_switches.h
index 94bf37f..ba3ed53 100644
--- a/ui/events/event_switches.h
+++ b/ui/events/event_switches.h
@@ -26,6 +26,10 @@
 EVENTS_BASE_EXPORT extern const char kTouchCalibration[];
 #endif
 
+#if defined(USE_X11)
+EVENTS_BASE_EXPORT extern const char kDispatchOneEventPerLoop[];
+#endif
+
 }  // namespace switches
 
 #endif  // UI_EVENTS_EVENTS_SWITCHES_H_
diff --git a/ui/events/platform/x11/x11_event_source.cc b/ui/events/platform/x11/x11_event_source.cc
index 5101f27..84451d1 100644
--- a/ui/events/platform/x11/x11_event_source.cc
+++ b/ui/events/platform/x11/x11_event_source.cc
@@ -9,8 +9,10 @@
 #include <X11/Xlib.h>
 #include <X11/XKBlib.h>
 
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "ui/events/devices/x11/device_data_manager_x11.h"
+#include "ui/events/event_switches.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
 #include "ui/events/platform/x11/x11_hotplug_event_handler.h"
@@ -81,6 +83,10 @@
   DeviceDataManagerX11::CreateInstance();
   InitializeXInput2(display_);
   InitializeXkb(display_);
+
+  base::CommandLine* cmdline = base::CommandLine::ForCurrentProcess();
+  dispatch_one_event_per_loop_ =
+      cmdline->HasSwitch(switches::kDispatchOneEventPerLoop);
 }
 
 X11EventSource::~X11EventSource() {
@@ -94,17 +100,19 @@
 ////////////////////////////////////////////////////////////////////////////////
 // X11EventSource, public
 
-void X11EventSource::DispatchXEvents() {
+bool X11EventSource::DispatchXEvents() {
   DCHECK(display_);
-  // Handle all pending events.
-  // It may be useful to eventually align this event dispatch with vsync, but
-  // not yet.
-  continue_stream_ = true;
-  while (XPending(display_) && continue_stream_) {
+
+  int pending_events = XPending(display_);
+  if (!pending_events)
+    return false;
+  do {
     XEvent xevent;
     XNextEvent(display_, &xevent);
     DispatchEvent(&xevent);
-  }
+  } while (--pending_events && continue_stream_ &&
+           !dispatch_one_event_per_loop_);
+  return true;
 }
 
 void X11EventSource::BlockUntilWindowMapped(XID window) {
diff --git a/ui/events/platform/x11/x11_event_source.h b/ui/events/platform/x11/x11_event_source.h
index d91fefe..2c3c4e3 100644
--- a/ui/events/platform/x11/x11_event_source.h
+++ b/ui/events/platform/x11/x11_event_source.h
@@ -28,9 +28,10 @@
 
   static X11EventSource* GetInstance();
 
-  // Called by the glib source dispatch function. Processes all (if any)
-  // available X events.
-  void DispatchXEvents();
+  // Processes pending X events.  Returns true if any events were dispatched.
+  // This function should be called repeatedly until it returns false to
+  // ensure all events are processed.
+  bool DispatchXEvents();
 
   // Blocks on the X11 event queue until we receive notification from the
   // xserver that |w| has been mapped; StructureNotifyMask events on |w| are
@@ -59,6 +60,9 @@
   // available events.
   bool continue_stream_;
 
+  // Dispatch one event at a time.
+  bool dispatch_one_event_per_loop_;
+
   scoped_ptr<X11HotplugEventHandler> hotplug_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(X11EventSource);
diff --git a/ui/events/platform/x11/x11_event_source_libevent.cc b/ui/events/platform/x11/x11_event_source_libevent.cc
index ff01d2e..c38cba4 100644
--- a/ui/events/platform/x11/x11_event_source_libevent.cc
+++ b/ui/events/platform/x11/x11_event_source_libevent.cc
@@ -14,6 +14,7 @@
 namespace {
 
 class X11EventSourceLibevent : public X11EventSource,
+                               public base::MessagePumpLibevent::EventSource,
                                public base::MessagePumpLibevent::Watcher {
  public:
   explicit X11EventSourceLibevent(XDisplay* display)
@@ -23,6 +24,8 @@
   }
 
   ~X11EventSourceLibevent() override {
+    if (initialized_)
+      base::MessageLoopForUI::current()->ClearEventSource();
   }
 
  private:
@@ -33,15 +36,18 @@
       return;
 
     int fd = ConnectionNumber(display());
-    base::MessageLoopForUI::current()->WatchFileDescriptor(fd, true,
-        base::MessagePumpLibevent::WATCH_READ, &watcher_controller_, this);
+    base::MessageLoopForUI::current()->WatchFileDescriptor(
+        fd, true, base::MessagePumpLibevent::WATCH_READ, &watcher_controller_,
+        this);
+    base::MessageLoopForUI::current()->SetEventSource(this);
     initialized_ = true;
   }
 
   // PlatformEventSource:
-  void OnDispatcherListChanged() override {
-    AddEventWatcher();
-  }
+  void OnDispatcherListChanged() override { AddEventWatcher(); }
+
+  // base::MessagePumpLibEvent::EventSource:
+  bool Poll() override { return DispatchXEvents(); }
 
   // base::MessagePumpLibevent::Watcher:
   void OnFileCanReadWithoutBlocking(int fd) override {