cc: Move scheduling logic out of OutputSurface

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 <deque>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/rolling_time_delta_history.h"
+#include "cc/output/begin_frame_args.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/overlay_candidate_validator.h"
 #include "cc/output/software_output_device.h"
-#include "cc/scheduler/frame_rate_controller.h"
 
 namespace base { class SingleThreadTaskRunner; }
 
 namespace ui { struct LatencyInfo; }
 
 namespace gfx {
 class Rect;
 class Size;
 class Transform;
 }
 
 namespace cc {
 
 class CompositorFrame;
 class CompositorFrameAck;
 struct ManagedMemoryPolicy;
 class OutputSurfaceClient;
 
 // 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 : public FrameRateControllerClient {
+class CC_EXPORT OutputSurface {
  public:
   enum {
     DEFAULT_MAX_FRAMES_PENDING = 2
   };
 
   explicit OutputSurface(scoped_refptr<ContextProvider> context_provider);
 
   explicit OutputSurface(scoped_ptr<SoftwareOutputDevice> software_device);
 
   OutputSurface(scoped_refptr<ContextProvider> context_provider,
@@ skipping 45 matching lines @@
 
   // 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);
 
   // Enable or disable vsync.
   void SetThrottleFrameProduction(bool enable);
 
-  void InitializeBeginFrameEmulation(base::SingleThreadTaskRunner* task_runner,
-                                     base::TimeDelta interval);
-
   virtual void EnsureBackbuffer();
   virtual void DiscardBackbuffer();
 
   virtual void Reshape(const gfx::Size& size, float scale_factor);
   virtual gfx::Size SurfaceSize() const;
 
   virtual void BindFramebuffer();
 
   // The implementation may destroy or steal the contents of the CompositorFrame
   // passed in (though it will not take ownership of the CompositorFrame
   // itself).
   virtual void SwapBuffers(CompositorFrame* frame);
 
   // 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) {}
 
   bool HasClient() { return !!client_; }
 
   // Returns an estimate of the current GPU latency. When only a software
   // device is present, returns 0.
   base::TimeDelta GpuLatencyEstimate();
 
   // Get the class capable of informing cc of hardware overlay capability.
   OverlayCandidateValidator* overlay_candidate_validator() const {
     return overlay_candidate_validator_.get();
   }
 
  protected:
+  // Note: DidSwapBuffers and OnSwapBuffersComplete should not be called on

[danakj, 2014/04/11 15:42:22]

In browser process land we've avoided doing things on the wrong OutputSurface by
generating an ID with each output surface and passing it around/binding it in
callbacks to identify the output surface. Then when we do stuff we check if the
id == the current output surface id and can respond accordingly. Would such a
thing work here?

[brianderson, 2014/04/11 20:21:28]

The id check works for making sure that an Ack for OS1 doesn't affect OS2
*after* we've created OS2.

The is_lost_ check makes sure that an Ack for OS1 doesn't make it to the
scheduler after we lose OS1 but *before* we've created OS2.

[danakj, 2014/04/14 18:19:27]

What if we reset the acks in flight and stuff when we create OS2 instead of when
we lose OS1. Could we stop caring about receiving those acks?

[brianderson, 2014/04/16 21:51:31]

Going to go with that solution and avoid being overly defensive in the
Scheduler.

+  // the client when the OutputSurface is lost to avoid race conditions where
+  // DidSwapBuffersComplete gets registered for an incorrect OutputSurface.
+  OutputSurfaceClient* client_;
+  bool is_lost_;
+
   // Synchronously initialize context3d and enter hardware mode.
   // This can only supported in threaded compositing mode.
   // |offscreen_context_provider| should match what is returned by
   // LayerTreeClient::OffscreenContextProvider().
   bool InitializeAndSetContext3d(
       scoped_refptr<ContextProvider> context_provider,
       scoped_refptr<ContextProvider> offscreen_context_provider);
   void ReleaseGL();
 
   void PostSwapBuffersComplete();
 
   struct OutputSurface::Capabilities capabilities_;
   scoped_refptr<ContextProvider> context_provider_;
   scoped_ptr<SoftwareOutputDevice> software_device_;
   scoped_ptr<OverlayCandidateValidator> overlay_candidate_validator_;
   gfx::Size surface_size_;
   float device_scale_factor_;
-  base::TimeDelta begin_frame_interval_;
 
-  // The FrameRateController is deprecated.
-  // Platforms should move to native BeginFrames instead.
   void CommitVSyncParameters(base::TimeTicks timebase,
                              base::TimeDelta interval);
-  virtual void FrameRateControllerTick(const BeginFrameArgs& args) OVERRIDE;
-  scoped_ptr<FrameRateController> frame_rate_controller_;
 
-  bool throttle_frame_production_;
-  bool needs_begin_frame_;
-  bool client_ready_for_begin_frame_;
-
-  // This stores a BeginFrame that we couldn't process immediately,
-  // but might process retroactively in the near future.
-  BeginFrameArgs skipped_begin_frame_args_;
-
-  // Forwarded to OutputSurfaceClient but threaded through OutputSurface
-  // first so OutputSurface has a chance to update the FrameRateController
   void SetNeedsRedrawRect(const gfx::Rect& damage_rect);
-  void BeginFrame(const BeginFrameArgs& args);
-  void DidSwapBuffers();
-  void OnSwapBuffersComplete();
   void ReclaimResources(const CompositorFrameAck* ack);
   void DidLoseOutputSurface();
   void SetExternalStencilTest(bool enabled);
   void SetExternalDrawConstraints(const gfx::Transform& transform,
                                   const gfx::Rect& viewport,
                                   const gfx::Rect& clip,
                                   bool valid_for_tile_management);
 
-  // virtual for testing.
-  virtual base::TimeTicks RetroactiveBeginFrameDeadline();
-  virtual void PostCheckForRetroactiveBeginFrame();
-  void CheckForRetroactiveBeginFrame();
-
  private:
-  OutputSurfaceClient* client_;
-
   void SetUpContext3d();
   void ResetContext3d();
   void SetMemoryPolicy(const ManagedMemoryPolicy& policy);
   void UpdateAndMeasureGpuLatency();
-
-  bool is_lost_;
-
-  // check_for_retroactive_begin_frame_pending_ is used to avoid posting
-  // redundant checks for a retroactive BeginFrame.
-  bool check_for_retroactive_begin_frame_pending_;
+  void OnSwapBuffersComplete();
 
   bool external_stencil_test_enabled_;
 
   base::WeakPtrFactory<OutputSurface> weak_ptr_factory_;
 
   std::deque<unsigned> available_gpu_latency_query_ids_;
   std::deque<unsigned> pending_gpu_latency_query_ids_;
   RollingTimeDeltaHistory gpu_latency_history_;
 
   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OUTPUT_SURFACE_H_