Add a Javascript wrapper around ServiceRegistry and expose it to WebUI.

content/common/mojo/service_registry_impl.h

Index: content/common/mojo/service_registry_impl.h
diff --git a/content/common/mojo/service_registry_impl.h b/content/common/mojo/service_registry_impl.h
index 8e60b3756b7299faf24f063a059418a8c51d55cd..e4b053e9e1f5fd5359d9c4aff862e84cb60631f6 100644
--- a/content/common/mojo/service_registry_impl.h
+++ b/content/common/mojo/service_registry_impl.h
@@ -41,6 +41,7 @@ class ServiceRegistryImpl
   virtual void GetRemoteInterface(
       const base::StringPiece& service_name,
       mojo::ScopedMessagePipeHandle handle) OVERRIDE;
+  virtual base::WeakPtr<ServiceRegistry> GetWeakPtr() OVERRIDE;
 
  private:
   // mojo::InterfaceImpl<mojo::IInterfaceProvider> overrides.
@@ -54,6 +55,8 @@ class ServiceRegistryImpl
   std::queue<std::pair<std::string, mojo::MessagePipeHandle> >
       pending_connects_;
   bool bound_;
+
+  base::WeakPtrFactory<ServiceRegistry> weak_factory_;
 };
 
 }  // namespace content