Force touch events to be dispatched on FNL

BUG=
R=cstout@chromium.org, jamesr@chromium.org

Review URL: https://codereview.chromium.org/1485233002 .

ui/ozone/platform/drm/BUILD.gn

diff --git a/ui/ozone/platform/drm/BUILD.gn b/ui/ozone/platform/drm/BUILD.gn
index 5f011b1..85e5c4d 100644
--- a/ui/ozone/platform/drm/BUILD.gn
+++ b/ui/ozone/platform/drm/BUILD.gn
@@ -110,6 +110,10 @@
     ]
   }
 
+  if (is_fnl) {
+    defines += [ "FORCE_DISPATCH_TOUCH_EVENTS" ]
+  }
+
   deps = [
     "//base",
     "//skia",

ui/ozone/platform/drm/host/drm_window_host.cc

diff --git a/ui/ozone/platform/drm/host/drm_window_host.cc b/ui/ozone/platform/drm/host/drm_window_host.cc
index 51c19ce..5cba0cb 100644
--- a/ui/ozone/platform/drm/host/drm_window_host.cc
+++ b/ui/ozone/platform/drm/host/drm_window_host.cc
@@ -128,6 +128,18 @@
     return grabber == widget_;
 
   if (event->IsTouchEvent()) {
+#ifdef FORCE_DISPATCH_TOUCH_EVENTS
+    // TODO(lanechr): This bypasses checks that ensure that touch events
+    // are dispatched to the right display.  The "right display" is defined as
+    // "the display associated with the touch device."  Displays are associated
+    // with touch devices through DeviceDataManager::UpdateTouchInfoForDisplay,
+    // which (as of today) is never called.
+    //
+    // I'm not sure yet how to best determine touchscreen/display association,
+    // but FNL currently only supports devices with one touch screen.  So for
+    // now, always dispatch touch events on FNL devices.
+    return true;
+#endif
     // Dispatch the event if it is from the touchscreen associated with the
     // DrmWindowHost. We cannot check the event's location because if the
     // touchscreen has a bezel, touches in the bezel have a location outside of