Compositor thread plumbing for layout rectangle debug info.

ui/compositor/layer.cc

Index: ui/compositor/layer.cc
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index a0858a6cca8248e92f9a9082d980456342174db8..2e2fc221767363997a5eb7eee43b2396607de301 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -667,6 +667,10 @@ std::string Layer::DebugName() {
   return name_;
 }
 
+scoped_refptr<base::debug::ConvertableToTraceFormat> Layer::TakeDebugInfo() {
+  return scoped_refptr<base::debug::ConvertableToTraceFormat>(NULL);

[danakj, 2013/12/03 00:38:18]

Maybe a TODO here to return some useful data so we can make use of this feature
for UI compositor, if that sounds right to you?

[chrishtr_gmail.com, 2013/12/03 00:44:08]

Done.

+}
+
 void Layer::OnAnimationStarted(const cc::AnimationEvent& event) {
   if (animator_.get())
     animator_->OnThreadedAnimationStarted(event);