[cc] Set BeginFrame sequence numbers on CompositorFrames from Scheduler.

cc/output/compositor_frame_metadata.h

 // Copyright (c) 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_COMPOSITOR_FRAME_METADATA_H_
 #define CC_OUTPUT_COMPOSITOR_FRAME_METADATA_H_
 
 #include <stdint.h>
 
 #include <vector>
 
 #include "cc/base/cc_export.h"
 #include "cc/input/selection.h"
+#include "cc/output/begin_frame_args.h"
 #include "cc/surfaces/surface_id.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/geometry/size_f.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 #include "ui/gfx/selection_bound.h"
 
 namespace cc {
 
 class CC_EXPORT CompositorFrameMetadata {
@@ skipping 57 matching lines @@
   // This indicates whether this CompositorFrame can be activated before
   // dependencies have been resolved.
   bool can_activate_before_dependencies = true;
 
   // This is a value that allows the browser to associate compositor frames
   // with the content that they represent -- typically top-level page loads.
   // TODO(kenrb, fsamuel): This should eventually by SurfaceID, when they
   // become available in all renderer processes. See https://crbug.com/695579.
   uint32_t content_source_id = 0;
 
+  // BeginFrameAck for the BeginFrame that this CompositorFrame answers.
+  BeginFrameAck begin_frame_ack;
+
  private:
   CompositorFrameMetadata(const CompositorFrameMetadata& other);
   CompositorFrameMetadata operator=(const CompositorFrameMetadata&) = delete;
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_COMPOSITOR_FRAME_METADATA_H_