Moves CustomFrameViewAsh to common

ash/mus/bridge/wm_shell_mus.cc

Index: ash/mus/bridge/wm_shell_mus.cc
diff --git a/ash/mus/bridge/wm_shell_mus.cc b/ash/mus/bridge/wm_shell_mus.cc
index 02943f8dab32d7a7577b6403ee4a3f5c52b06140..7215b943997d0c5997615e5b5cc2888a99eff7e6 100644
--- a/ash/mus/bridge/wm_shell_mus.cc
+++ b/ash/mus/bridge/wm_shell_mus.cc
@@ -14,6 +14,7 @@
 #include "ash/common/shell_observer.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/system/tray/default_system_tray_delegate.h"
+#include "ash/common/wm/immersive/wm_immersive_fullscreen_controller.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_event_handler.h"
 #include "ash/common/wm/maximize_mode/scoped_disable_internal_mouse_and_keyboard.h"
 #include "ash/common/wm/mru_window_tracker.h"
@@ -316,6 +317,12 @@ WmShellMus::CreateScopedDisableInternalMouseAndKeyboard() {
   return nullptr;
 }
 
+std::unique_ptr<WmImmersiveFullscreenController>
+WmShellMus::CreateImmersiveFullscreenController() {
+  // TODO(sky): port ImmersiveFullscreenController, http://crbug.com/548435.
+  return nullptr;
+}
+
 void WmShellMus::OnOverviewModeStarting() {
   FOR_EACH_OBSERVER(ShellObserver, *shell_observers(),
                     OnOverviewModeStarting());