cc: Introduce BeginFrame sequence numbers and acknowledgements.

cc/surfaces/display.h

 // Copyright 2014 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_SURFACES_DISPLAY_H_
 #define CC_SURFACES_DISPLAY_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "cc/output/output_surface_client.h"
 #include "cc/resources/returned_resource.h"
-#include "cc/scheduler/begin_frame_source.h"
 #include "cc/surfaces/display_scheduler.h"
 #include "cc/surfaces/frame_sink_id.h"
 #include "cc/surfaces/surface_aggregator.h"
 #include "cc/surfaces/surface_id.h"
 #include "cc/surfaces/surface_manager.h"
 #include "cc/surfaces/surfaces_export.h"
 #include "gpu/command_buffer/common/texture_in_use_response.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/color_space.h"
 
 namespace gpu {
 class GpuMemoryBufferManager;
 }
 
 namespace gfx {
 class Size;
 }
 
 namespace cc {
 
 class BeginFrameSource;
 class DirectRenderer;
+class DisplayBeginFrameSource;
 class DisplayClient;
 class OutputSurface;
 class RendererSettings;
 class ResourceProvider;
 class SharedBitmapManager;
 class SoftwareRenderer;
 class SurfaceAggregator;
 class TextureMailboxDeleter;
 
 // A Display produces a surface that can be used to draw to a physical display
@@ skipping 41 matching lines @@
   void OnSurfaceDamaged(const SurfaceId& surface, bool* changed) override;
   void OnSurfaceCreated(const SurfaceId& surface_id,
                         const gfx::Size& frame,
                         float device_scale_factor) override;
 
   bool has_scheduler() const { return !!scheduler_; }
   DirectRenderer* renderer_for_testing() const { return renderer_.get(); }
 
   void ForceImmediateDrawAndSwapIfPossible();
 
+  // Swap the Display's current BeginFrameSource with the provided one. The
+  // provided unique_ptr will be updated to point to the previous source. Used
+  // to set an ExternalBeginFrameSource for manual control over BeginFrames
+  // through DevTools.
+  void SwapBeginFrameSource(
+      std::unique_ptr<BeginFrameSource>* begin_frame_source);
+
  private:
   void InitializeRenderer();
   void UpdateRootSurfaceResourcesLocked();
   void DidLoseContextProvider();
 
   SharedBitmapManager* const bitmap_manager_;
   gpu::GpuMemoryBufferManager* const gpu_memory_buffer_manager_;
   const RendererSettings settings_;
 
   DisplayClient* client_ = nullptr;
   SurfaceManager* surface_manager_ = nullptr;
   const FrameSinkId frame_sink_id_;
   SurfaceId current_surface_id_;
   gfx::Size current_surface_size_;
   float device_scale_factor_ = 1.f;
   gfx::ColorSpace device_color_space_;
   bool visible_ = false;
   bool swapped_since_resize_ = false;
   bool output_is_secure_ = false;
 
   // The begin_frame_source_ is often known by the output_surface_ and
   // the scheduler_.
-  std::unique_ptr<BeginFrameSource> begin_frame_source_;
+  std::unique_ptr<DisplayBeginFrameSource> begin_frame_source_;
   std::unique_ptr<OutputSurface> output_surface_;
   std::unique_ptr<DisplayScheduler> scheduler_;
   std::unique_ptr<ResourceProvider> resource_provider_;
   std::unique_ptr<SurfaceAggregator> aggregator_;
   std::unique_ptr<TextureMailboxDeleter> texture_mailbox_deleter_;
   std::unique_ptr<DirectRenderer> renderer_;
   SoftwareRenderer* software_renderer_ = nullptr;
   std::vector<ui::LatencyInfo> stored_latency_info_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Display);
 };
 
 }  // namespace cc
 
 #endif  // CC_SURFACES_DISPLAY_H_