[Refactor] Introduce MediaDelegate

ash/test/test_shell_delegate.cc

Index: ash/test/test_shell_delegate.cc
diff --git a/ash/test/test_shell_delegate.cc b/ash/test/test_shell_delegate.cc
index b7a4823d936dac2aaeeae36958595a363dd2c013..29986c3e9451e07ab7837934efc196d366488034 100644
--- a/ash/test/test_shell_delegate.cc
+++ b/ash/test/test_shell_delegate.cc
@@ -10,6 +10,7 @@
 #include "ash/default_accessibility_delegate.h"
 #include "ash/host/root_window_host_factory.h"
 #include "ash/keyboard_controller_proxy_stub.h"
+#include "ash/media_delegate.h"
 #include "ash/new_window_delegate.h"
 #include "ash/session_state_delegate.h"
 #include "ash/shell.h"
@@ -40,6 +41,13 @@ class NewWindowDelegateImpl : public NewWindowDelegate {
   virtual void OpenFeedbackPage() OVERRIDE {}
 };
 
+class MediaDelegateImpl : public MediaDelegate {
+ public:
+  virtual void HandleMediaNextTrack() OVERRIDE {}
+  virtual void HandleMediaPlayPause() OVERRIDE {}
+  virtual void HandleMediaPrevTrack() OVERRIDE {}
+};
+
 }  // namespace
 
 TestShellDelegate::TestShellDelegate()
@@ -121,6 +129,10 @@ NewWindowDelegate* TestShellDelegate::CreateNewWindowDelegate() {
   return new NewWindowDelegateImpl;
 }
 
+MediaDelegate* TestShellDelegate::CreateMediaDelegate() {
+  return new MediaDelegateImpl;
+}
+
 aura::client::UserActionClient* TestShellDelegate::CreateUserActionClient() {
   return NULL;
 }
@@ -128,15 +140,6 @@ aura::client::UserActionClient* TestShellDelegate::CreateUserActionClient() {
 void TestShellDelegate::RecordUserMetricsAction(UserMetricsAction action) {
 }
 
-void TestShellDelegate::HandleMediaNextTrack() {
-}
-
-void TestShellDelegate::HandleMediaPlayPause() {
-}
-
-void TestShellDelegate::HandleMediaPrevTrack() {
-}
-
 ui::MenuModel* TestShellDelegate::CreateContextMenu(aura::Window* root) {
   return NULL;
 }