cc: Emulate BeginFrame in OutputSurfaces that don't support it natively

cc/output/output_surface.h

Index: cc/output/output_surface.h
diff --git a/cc/output/output_surface.h b/cc/output/output_surface.h
index d6f4b82ed8b64d9a9d81a87d52a5b0552746c852..a1f1ce5a62c4ae572d013dd3abc0721c0976c93b 100644
--- a/cc/output/output_surface.h
+++ b/cc/output/output_surface.h
@@ -9,6 +9,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/output/software_output_device.h"
+#include "cc/scheduler/frame_rate_controller.h"
 #include "third_party/WebKit/public/platform/WebGraphicsContext3D.h"
 
 namespace ui { struct LatencyInfo; }
@@ -21,8 +22,10 @@ class Size;
 namespace cc {
 
 class CompositorFrame;
+class CompositorFrameAck;
 class OutputSurfaceClient;
 class OutputSurfaceCallbacks;
+class Thread;
 
 // Represents the output surface for a compositor. The compositor owns
 // and manages its destruction. Its lifetime is:
@@ -31,7 +34,7 @@ class OutputSurfaceCallbacks;
 //      From here on, it will only be used on the compositor thread.
 //   3. If the 3D context is lost, then the compositor will delete the output
 //      surface (on the compositor thread) and go back to step 1.
-class CC_EXPORT OutputSurface {
+class CC_EXPORT OutputSurface : public FrameRateControllerClient {
  public:
   explicit OutputSurface(scoped_ptr<WebKit::WebGraphicsContext3D> context3d);
 
@@ -79,6 +82,12 @@ class CC_EXPORT OutputSurface {
   // this point on the output surface will only be used on the compositor
   // thread.
   virtual bool BindToClient(OutputSurfaceClient* client);
+  void InitializeBeginFrameEmulation(
+    Thread* thread,
+    bool throttle_frame_production,
+    base::TimeDelta interval,
+    int max_frames_pending,
+    bool swap_buffers_complete_supported);
 
   // Sends frame data to the parent compositor. This should only be called when
   // capabilities().has_parent_compositor. The implementation may destroy or
@@ -102,10 +111,13 @@ class CC_EXPORT OutputSurface {
   // Requests a BeginFrame notification from the output surface. The
   // notification will be delivered by calling
   // OutputSurfaceClient::BeginFrame until the callback is disabled.
-  virtual void SetNeedsBeginFrame(bool enable) {}
+  virtual void SetNeedsBeginFrame(bool enable);
 
- protected:
+ private:
   OutputSurfaceClient* client_;
+  friend class OutputSurfaceCallbacks;
+
+ protected:
   struct cc::OutputSurface::Capabilities capabilities_;
   scoped_ptr<WebKit::WebGraphicsContext3D> context3d_;
   scoped_ptr<cc::SoftwareOutputDevice> software_device_;
@@ -113,7 +125,25 @@ class CC_EXPORT OutputSurface {
 
   scoped_ptr<OutputSurfaceCallbacks> callbacks_;
 
- private:
+  // The FrameRateController is deprecated.
+  // Platforms should move to native BeginFrames instead.
+  void OnVSyncParametersChanged(base::TimeTicks timebase,
+                                base::TimeDelta interval);
+  virtual void FrameRateControllerTick(bool throttled) OVERRIDE;
+  scoped_ptr<FrameRateController> frame_rate_controller_;
+  int pending_begin_frames_;
+  int pending_swap_buffers_;
+
+  // Forwarded to OutputSurfaceClient but threaded through OutputSurface
+  // first so OutputSurface has a chance to update the FrameRateController
+  bool hasClient() { return !!client_; }
+  void SetNeedsRedrawRect(gfx::Rect damage_rect);
+  void BeginFrame(base::TimeTicks frame_time);
+  void OnSendFrameToParentCompositorAck(const CompositorFrameAck&);
+  void DidSwapBuffers();
+  void OnSwapBuffersComplete();
+  void DidLoseOutputSurface();
+
   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
 };