Add layer name into frame viewer

cc/layers/content_layer_client.h

Index: cc/layers/content_layer_client.h
diff --git a/cc/layers/content_layer_client.h b/cc/layers/content_layer_client.h
index e59c1d8c3e10a48d3a79bd7783eed0379a783a62..fc5aa6f9c48c9e262d5a096d03970173ffd42936 100644
--- a/cc/layers/content_layer_client.h
+++ b/cc/layers/content_layer_client.h
@@ -5,6 +5,8 @@
 #ifndef CC_LAYERS_CONTENT_LAYER_CLIENT_H_
 #define CC_LAYERS_CONTENT_LAYER_CLIENT_H_
 
+#include <string>
+
 #include "cc/base/cc_export.h"
 
 class SkCanvas;
@@ -25,6 +27,7 @@ class CC_EXPORT ContentLayerClient {
   // Called by the content layer during the update phase.
   // If the client paints LCD text, it may want to invalidate the layer.
   virtual void DidChangeLayerCanUseLCDText() = 0;
+  virtual std::string DebugName() { return std::string(); }
 
  protected:
   virtual ~ContentLayerClient() {}