Update from https://crrev.com/316786

cc/layers/layer.h

Index: cc/layers/layer.h
diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index cf1356c852c7d710caeb2efca82f22a507469421..873f360a238c3944d4c2f3a67c025125fc2063ce 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -47,13 +47,7 @@ namespace base {
 namespace trace_event {
 class ConvertableToTraceFormat;
 }
-
-// TODO(ssid): remove these aliases after the tracing clients are moved to the
-// new trace_event namespace. See crbug.com/451032. ETA: March 2015
-namespace debug {
-using ::base::trace_event::ConvertableToTraceFormat;
 }
-}  // namespace base
 
 namespace cc {
 
@@ -383,7 +377,8 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   virtual void OnOutputSurfaceCreated() {}
   virtual bool IsSuitableForGpuRasterization() const;
 
-  virtual scoped_refptr<base::debug::ConvertableToTraceFormat> TakeDebugInfo();
+  virtual scoped_refptr<base::trace_event::ConvertableToTraceFormat>
+  TakeDebugInfo();
 
   void SetLayerClient(LayerClient* client) { client_ = client; }