cc: Some API cleanup.

LayerTreeFrameSinkClient::DidNotNeedBeginFrame() is never used
from LayerTreeFrameSink instances. So it is removed. However,
LayerTreeHostImpl::DidNotNeedBeginFrame() is still used to notify
when the compositor stops asking for begin-frames, so keep it as
a direct member function.

BUG=none
TBR=oshima@ for mechanical changes in ash/ and components/exo

Change-Id: Ia5b7dac845e12a487e25f635cdc6ee9d8de2bd26
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1692485
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#675741}

ash/components/fast_ink/fast_ink_view.cc

@@ -240,7 +240,6 @@ class FastInkView::LayerTreeFrameSinkHolder
     if (root_window_)
       ScheduleDelete();
   }
-  void DidNotNeedBeginFrame() override {}
   void OnDraw(const gfx::Transform& transform,
               const gfx::Rect& viewport,
               bool resourceless_software_draw,

cc/test/fake_layer_tree_frame_sink_client.h

@@ -24,7 +24,6 @@ class FakeLayerTreeFrameSinkClient : public LayerTreeFrameSinkClient {
   void ReclaimResources(
       const std::vector<viz::ReturnedResource>& resources) override {}
   void DidLoseLayerTreeFrameSink() override;
-  void DidNotNeedBeginFrame() override {}
   void SetExternalTilePriorityConstraints(
       const gfx::Rect& viewport_rect_for_tile_priority,
       const gfx::Transform& transform_for_tile_priority) override {}

cc/trees/layer_tree_frame_sink_client.h

@@ -68,9 +68,6 @@ class CC_EXPORT LayerTreeFrameSinkClient {
   // viz::ContextProviders) must be recreated.
   virtual void DidLoseLayerTreeFrameSink() = 0;
 
-  // Notification that the client does not need a new BeginFrame.
-  virtual void DidNotNeedBeginFrame() = 0;
-
   // For SynchronousCompositor (WebView) to ask the layer compositor to submit
   // a new CompositorFrame synchronously.
   virtual void OnDraw(const gfx::Transform& transform,

cc/trees/layer_tree_host_impl.cc

@@ -3324,13 +3324,14 @@ void LayerTreeHostImpl::ReleaseLayerTreeFrameSink() {
   // If gpu compositing, then any resources created with the gpu context in the
   // LayerTreeFrameSink were exported to the display compositor may be modified
   // by it, and thus we would be unable to determine what state they are in, in
-  // order to reuse them, so they must be lost. Note that this includes resources
-  // created using the gpu context associated with |layer_tree_frame_sink_|
-  // internally by the compositor and any resources received from an external
-  // source (for instance, TextureLayers). This is because the API contract
-  // for releasing these external resources requires that the compositor return
-  // them with a valid sync token and no modifications to their GL state. Since
-  // that can not be guaranteed, these must also be marked lost.
+  // order to reuse them, so they must be lost. Note that this includes
+  // resources created using the gpu context associated with
+  // |layer_tree_frame_sink_| internally by the compositor and any resources
+  // received from an external source (for instance, TextureLayers). This is
+  // because the API contract for releasing these external resources requires
+  // that the compositor return them with a valid sync token and no
+  // modifications to their GL state. Since that can not be guaranteed, these
+  // must also be marked lost.
   //
   // In software compositing, the resources are not modified by the display
   // compositor (there is no stateful metadata for shared memory), so we do not
@@ -3338,9 +3339,9 @@ void LayerTreeHostImpl::ReleaseLayerTreeFrameSink() {
   //
   // In both cases, the resources that are exported to the display compositor
   // will have no means of being returned to this client without the
-  // LayerTreeFrameSink, so they should no longer be considered as exported.
-  // Do this *after* any interactions with the |layer_tree_frame_sink_| in case
-  // it tries to return resources during destruction.
+  // LayerTreeFrameSink, so they should no longer be considered as exported. Do
+  // this *after* any interactions with the |layer_tree_frame_sink_| in case it
+  // tries to return resources during destruction.
   //
   // The assumption being made here is that the display compositor WILL NOT use
   // any resources previously exported when the CompositorFrameSink is closed.

cc/trees/layer_tree_host_impl.h

@@ -439,6 +439,8 @@ class CC_EXPORT LayerTreeHostImpl : public InputHandler,
 
   DrawMode GetDrawMode() const;
 
+  void DidNotNeedBeginFrame();
+
   // TileManagerClient implementation.
   void NotifyReadyToActivate() override;
   void NotifyReadyToDraw() override;
@@ -478,7 +480,6 @@ class CC_EXPORT LayerTreeHostImpl : public InputHandler,
   void DidPresentCompositorFrame(
       uint32_t frame_token,
       const gfx::PresentationFeedback& feedback) override;
-  void DidNotNeedBeginFrame() override;
   void ReclaimResources(
       const std::vector<viz::ReturnedResource>& resources) override;
   void SetMemoryPolicy(const ManagedMemoryPolicy& policy) override;

components/exo/layer_tree_frame_sink_holder.h

@@ -57,7 +57,6 @@ class LayerTreeFrameSinkHolder : public cc::LayerTreeFrameSinkClient,
       uint32_t presentation_token,
       const gfx::PresentationFeedback& feedback) override;
   void DidLoseLayerTreeFrameSink() override;
-  void DidNotNeedBeginFrame() override {}
   void OnDraw(const gfx::Transform& transform,
               const gfx::Rect& viewport,
               bool resourceless_software_draw,