Ash: Support "Next Song", "Previous Song", "Play/Pause" Multi Media buttons

ash/shell/shell_delegate_impl.cc

Index: ash/shell/shell_delegate_impl.cc
diff --git a/ash/shell/shell_delegate_impl.cc b/ash/shell/shell_delegate_impl.cc
index 383218d424358ebb7b14f8c58562da43951b2c78..b7457e640bbb0a7db7b0c4f175e3ad3db35b0c50 100644
--- a/ash/shell/shell_delegate_impl.cc
+++ b/ash/shell/shell_delegate_impl.cc
@@ -133,5 +133,14 @@ void ShellDelegateImpl::OpenFeedbackPage() {
 void ShellDelegateImpl::RecordUserMetricsAction(UserMetricsAction action) {
 }
 
+void ShellDelegateImpl::HandleMediaNextTrack() {
+}
+
+void ShellDelegateImpl::HandleMediaPlayPause() {
+}
+
+void ShellDelegateImpl::HandleMediaPrevTrack() {
+}
+
 }  // namespace shell
 }  // namespace ash