Mac: Add detection for low power video compatible frames

ui/accelerated_widget_mac/ca_layer_tree_coordinator.h

Index: ui/accelerated_widget_mac/ca_layer_tree_coordinator.h
diff --git a/ui/accelerated_widget_mac/ca_layer_tree_coordinator.h b/ui/accelerated_widget_mac/ca_layer_tree_coordinator.h
index f479afe1c59985977d40fc2627c7b1ccceaeda0f..18d34e91589243a8a2369665c7eb1b735cb8e496 100644
--- a/ui/accelerated_widget_mac/ca_layer_tree_coordinator.h
+++ b/ui/accelerated_widget_mac/ca_layer_tree_coordinator.h
@@ -38,11 +38,17 @@ class ACCELERATED_WIDGET_MAC_EXPORT CALayerTreeCoordinator {
 
   // Commit the pending frame's OpenGL backbuffer or CALayer tree to be
   // attached to the root CALayer.
-  void CommitPendingTreesToCA(const gfx::Rect& pixel_damage_rect);
+  void CommitPendingTreesToCA(const gfx::Rect& pixel_damage_rect,
+                              bool* fullscreen_low_power_layer_valid);

[erikchen, 2016/04/26 23:56:21]

Add the comment:
If the pending tree should be displayed as a fullscreen low power layer, then
the output variable |fullscreen_low_power_layer_valid| will be set to true.

[ccameron, 2016/04/27 20:01:10]

Done.

 
-  // Get the root CALayer to display the current frame.
+  // Get the root CALayer to display the current frame. This does not change
+  // over the lifetime of the object.
   CALayer* GetCALayerForDisplay() const;
 
+  // Get the CALayer to display fullscreen low power content. This does not
+  // change over the lifetime of the object.
+  CALayer* GetFullscreenLowPowerLayerForDisplay() const;
+
   // Get the current frame's OpenGL backbuffer IOSurface. This is only needed
   // when not using remote layers.
   IOSurfaceRef GetIOSurfaceForDisplay();
@@ -53,6 +59,7 @@ class ACCELERATED_WIDGET_MAC_EXPORT CALayerTreeCoordinator {
   float scale_factor_ = 1;
 
   base::scoped_nsobject<CALayer> root_ca_layer_;
+  base::scoped_nsobject<AVSampleBufferDisplayLayer> fullscreen_low_power_layer_;
 
   // Frame that has been scheduled, but has not had a subsequent commit call
   // made yet.
@@ -62,6 +69,7 @@ class ACCELERATED_WIDGET_MAC_EXPORT CALayerTreeCoordinator {
   // Frame that is currently being displayed on the screen.
   std::unique_ptr<GLRendererLayerTree> current_gl_renderer_layer_tree_;
   std::unique_ptr<CARendererLayerTree> current_ca_renderer_layer_tree_;
+  bool current_fullscreen_low_power_layer_valid_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(CALayerTreeCoordinator);
 };