Plumb cc::LatencyInfo through command buffer and output surface

cc/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_SURFACE_H_
 #define CC_OUTPUT_SURFACE_H_
 
 #define USE_CC_OUTPUT_SURFACE // TODO(danakj): Remove this.
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/cc_export.h"
 #include "cc/software_output_device.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebCompositorOutputSurface.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
 
 namespace gfx {
 class Rect;
 class Size;
 }
 
 namespace cc {
 
 class CompositorFrame;
 class OutputSurfaceClient;
+struct LatencyInfo;
 
 // 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 WebKit::WebCompositorOutputSurface {
  public:
@@ skipping 49 matching lines @@
 
   virtual void BindFramebuffer();
 
   virtual void PostSubBuffer(gfx::Rect rect);
   virtual void SwapBuffers();
 
   // Notifies frame-rate smoothness preference. If true, all non-critical
   // processing should be stopped, or lowered in priority.
   virtual void UpdateSmoothnessTakesPriority(bool prefer_smoothness) {}
 
+  virtual void SetLatencyInfo(const LatencyInfo&) {}

[piman, 2013/03/19 04:30:29]

What calls this, and in particular, what ensures ordering wrt the swap (i.e.
calls Flush)? What is the proper ordering?

Agreed with Nat, this should probably be folded into
SwapBuffers/PostSubBuffer/SendFrameToParentCompositor (and the 2 former maybe
folded into the latter).

+
  protected:
   OutputSurfaceClient* client_;
   struct cc::OutputSurface::Capabilities capabilities_;
   scoped_ptr<WebKit::WebGraphicsContext3D> context3d_;
   scoped_ptr<cc::SoftwareOutputDevice> software_device_;
   bool has_gl_discard_backbuffer_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_SURFACE_H_