Adding support for VSyncProvider to the software drawing path

cc/output/software_output_device.cc

 // Copyright 2013 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.
 
 #include "cc/output/software_output_device.h"
 
 #include "base/logging.h"
 #include "cc/output/software_frame_data.h"
 #include "third_party/skia/include/core/SkBitmapDevice.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "ui/gfx/skia_util.h"
+#include "ui/gl/vsync_provider.h"
 
 namespace cc {
 
 SoftwareOutputDevice::SoftwareOutputDevice() {}
 
 SoftwareOutputDevice::~SoftwareOutputDevice() {}
 
 void SoftwareOutputDevice::Resize(gfx::Size viewport_size) {
   if (viewport_size_ == viewport_size)
     return;
@@ skipping 27 matching lines @@
 
 void SoftwareOutputDevice::Scroll(
     gfx::Vector2d delta, gfx::Rect clip_rect) {
   NOTIMPLEMENTED();
 }
 
 void SoftwareOutputDevice::ReclaimSoftwareFrame(unsigned id) {
   NOTIMPLEMENTED();
 }
 
+gfx::VSyncProvider* SoftwareOutputDevice::GetVSyncProvider() {
+  return vsync_provider_.get();
+}
+
 }  // namespace cc