rendering_helper - Schedule RenderContent() based on VSync.

content/common/gpu/media/rendering_helper.h

Index: content/common/gpu/media/rendering_helper.h
diff --git a/content/common/gpu/media/rendering_helper.h b/content/common/gpu/media/rendering_helper.h
index ce7f4e192b57e6ad448e6f697655b6970e3c5bdd..b080f6816ce180d517b655e212ea5150fadb77df 100644
--- a/content/common/gpu/media/rendering_helper.h
+++ b/content/common/gpu/media/rendering_helper.h
@@ -129,17 +129,14 @@ class RenderingHelper {
     // The rect on the screen where the video will be rendered.
     gfx::Rect render_area;
 
-    // True if the last (and the only one) frame in pending_frames has
-    // been rendered. We keep the last remaining frame in pending_frames even
-    // after it has been rendered, so that we have something to display if the
-    // client is falling behind on providing us with new frames during
-    // timer-driven playback.
-    bool last_frame_rendered;
-
     // True if there won't be any new video frames comming.
     bool is_flushing;
 
-    // The number of frames need to be dropped to catch up the rendering.
+    // The number of frames need to be dropped to catch up the rendering. We
+    // always keep the last remaining frame in pending_frames even after it
+    // has been rendered, so that we have something to display if the client
+    // is falling behind on providing us with new frames during timer-driven
+    // playback.
     int frames_to_drop;
 
     // The video frames pending for rendering.
@@ -157,6 +154,13 @@ class RenderingHelper {
 
   void LayoutRenderingAreas(const std::vector<gfx::Size>& window_sizes);
 
+  void UpdateVSyncParameters(base::WaitableEvent* done,
+                             const base::TimeTicks timebase,
+                             const base::TimeDelta interval);
+
+  void DropOneFrameForAllVideos();
+  void ScheduleNextRenderContent();
+
   // Render |texture_id| to the current view port of the screen using target
   // |texture_target|.
   void RenderTexture(uint32 texture_target, uint32 texture_id);
@@ -182,6 +186,8 @@ class RenderingHelper {
   base::TimeDelta frame_duration_;
   base::TimeTicks scheduled_render_time_;
   base::CancelableClosure render_task_;
+  base::TimeTicks vsync_timebase_;
+  base::TimeDelta vsync_interval_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderingHelper);
 };