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

cc/output/output_surface.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_OUTPUT_OUTPUT_SURFACE_H_
 #define CC_OUTPUT_OUTPUT_SURFACE_H_
 
 #include "base/basictypes.h"
 #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; }
 
 namespace gfx {
 class Rect;
 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:
 //   1. Created on the main thread by the LayerTreeHost through its client.
 //   2. Passed to the compositor thread and bound to a client via BindToClient.
 //      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);
 
   explicit OutputSurface(scoped_ptr<cc::SoftwareOutputDevice> software_device);
 
   OutputSurface(scoped_ptr<WebKit::WebGraphicsContext3D> context3d,
                 scoped_ptr<cc::SoftwareOutputDevice> software_device);
 
   virtual ~OutputSurface();
 
@@ skipping 28 matching lines @@
   // (namely Android WebView), this is called to determine whether the software
   // device should be used on the current frame.
   virtual bool ForcedDrawToSoftwareDevice() const;
 
   // Called by the compositor on the compositor thread. This is a place where
   // thread-specific data for the output surface can be initialized, since from
   // 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,
+    bool swap_buffers_complete_supported);
+
+  void SetMaxFramesPending(int max_frames_pending);
+
   // Sends frame data to the parent compositor. This should only be called when
   // capabilities().has_parent_compositor. The implementation may destroy or
   // steal the contents of the CompositorFrame passed in.
   virtual void SendFrameToParentCompositor(CompositorFrame* frame);
 
   virtual void EnsureBackbuffer();
   virtual void DiscardBackbuffer();
 
   virtual void Reshape(gfx::Size size, float scale_factor);
 
   virtual void BindFramebuffer();
 
   virtual void PostSubBuffer(gfx::Rect rect, const ui::LatencyInfo&);
   virtual void SwapBuffers(const ui::LatencyInfo&);
 
   // Notifies frame-rate smoothness preference. If true, all non-critical
   // processing should be stopped, or lowered in priority.
   virtual void UpdateSmoothnessTakesPriority(bool prefer_smoothness) {}
 
   // 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);
+
+ private:
+  OutputSurfaceClient* client_;
+  friend class OutputSurfaceCallbacks;
 
  protected:
-  OutputSurfaceClient* client_;
   struct cc::OutputSurface::Capabilities capabilities_;
   scoped_ptr<WebKit::WebGraphicsContext3D> context3d_;
   scoped_ptr<cc::SoftwareOutputDevice> software_device_;
   bool has_gl_discard_backbuffer_;
 
   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 max_frames_pending_;
+  int pending_swap_buffers_;
+  bool begin_frame_pending_;
+
+  // 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);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OUTPUT_SURFACE_H_