cc: Make scheduling be driven by vsync for android webview.

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"
@@ skipping 133 matching lines @@
   bool HasClient() { return !!client_; }
 
   // Get the class capable of informing cc of hardware overlay capability.
   OverlayCandidateValidator* overlay_candidate_validator() const {
     return overlay_candidate_validator_.get();
   }
 
   void DidLoseOutputSurface();
   void SetMemoryPolicy(const ManagedMemoryPolicy& policy);
 
+  // Support for a pull-model where draws are requested by the output surface.
+  //
+  // OutputSurface::Invalidate is called by the compositor to notify that
+  // there's new content.
+  virtual void Invalidate() {}

[brianderson, 2015/03/25 23:10:37]

Might want to update comments somewhere describing SwapBuffers as the push
model.

[sunnyps, 2015/03/27 00:52:48]

In both the push and pull model, swap buffers is called. The difference is who
decides when that happens.

+
  protected:
   OutputSurfaceClient* client_;
 
   // Synchronously initialize context3d and enter hardware mode.
   // This can only supported in threaded compositing mode.
   bool InitializeAndSetContext3d(
       scoped_refptr<ContextProvider> context_provider,
       scoped_refptr<ContextProvider> worker_context_provider);
   void ReleaseGL();
 
@@ skipping 28 matching lines @@
   bool external_stencil_test_enabled_;
 
   base::WeakPtrFactory<OutputSurface> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OUTPUT_SURFACE_H_