Add LayerTreeHostSettings for synchronous compositor

cc/scheduler/vsync_time_source.h

Index: cc/scheduler/vsync_time_source.h
diff --git a/cc/scheduler/vsync_time_source.h b/cc/scheduler/vsync_time_source.h
index 910168f26bdc315c9d3b428bd0634d28b1539078..03e32ff68357fc8327c12ac9706d429c76ad004b 100644
--- a/cc/scheduler/vsync_time_source.h
+++ b/cc/scheduler/vsync_time_source.h
@@ -33,7 +33,8 @@ class VSyncProvider {
 // external vsync signal.
 class CC_EXPORT VSyncTimeSource : public TimeSource, public VSyncClient {
  public:
-  static scoped_refptr<VSyncTimeSource> Create(VSyncProvider* vsync_provider);
+  static scoped_refptr<VSyncTimeSource> Create(
+      VSyncProvider* vsync_provider, bool lazy_disable);

[Sami, 2013/05/03 17:02:55]

Instead of a bool could you make this into an enum? That way it's a little more
obvious what the parameter does at the call site.

[boliu, 2013/05/03 17:20:39]

Done.

 
   // TimeSource implementation
   virtual void SetClient(TimeSourceClient* client) OVERRIDE;
@@ -48,7 +49,7 @@ class CC_EXPORT VSyncTimeSource : public TimeSource, public VSyncClient {
   virtual void DidVSync(base::TimeTicks frame_time) OVERRIDE;
 
  protected:
-  explicit VSyncTimeSource(VSyncProvider* vsync_provider);
+  explicit VSyncTimeSource(VSyncProvider* vsync_provider, bool lazy_disable);
   virtual ~VSyncTimeSource();
 
   base::TimeTicks last_tick_time_;
@@ -58,6 +59,7 @@ class CC_EXPORT VSyncTimeSource : public TimeSource, public VSyncClient {
 
   VSyncProvider* vsync_provider_;
   TimeSourceClient* client_;
+  bool lazy_disable_;
 
   DISALLOW_COPY_AND_ASSIGN(VSyncTimeSource);
 };