Merges RootWindowControllerCommon into WmRootWindowController

ash/mus/bridge/wm_root_window_controller_mus.h

Index: ash/mus/bridge/wm_root_window_controller_mus.h
diff --git a/ash/mus/bridge/wm_root_window_controller_mus.h b/ash/mus/bridge/wm_root_window_controller_mus.h
index 067182099486de6a764e11caff334c6f6eac9b37..a154256c636e1b78fc663d053530e1f3918d5eb6 100644
--- a/ash/mus/bridge/wm_root_window_controller_mus.h
+++ b/ash/mus/bridge/wm_root_window_controller_mus.h
@@ -7,7 +7,6 @@
 
 #include "ash/common/wm_root_window_controller.h"
 #include "base/macros.h"
-#include "base/observer_list.h"
 
 namespace display {
 class Display;
@@ -52,10 +51,6 @@ class WmRootWindowControllerMus : public WmRootWindowController {
   // WmRootWindowController:
   bool HasShelf() override;
   WmShell* GetShell() override;
-  wm::WorkspaceWindowState GetWorkspaceWindowState() override;
-  void SetMaximizeBackdropDelegate(
-      std::unique_ptr<WorkspaceLayoutManagerBackdropDelegate> delegate)
-      override;
   AlwaysOnTopController* GetAlwaysOnTopController() override;
   WmShelf* GetShelf() override;
   WmWindow* GetWindow() override;
@@ -65,10 +60,10 @@ class WmRootWindowControllerMus : public WmRootWindowController {
       views::Widget::InitParams* init_params) override;
   WmWindow* FindEventTarget(const gfx::Point& location_in_screen) override;
   gfx::Point GetLastMouseLocationInRoot() override;
-  void AddObserver(WmRootWindowControllerObserver* observer) override;
-  void RemoveObserver(WmRootWindowControllerObserver* observer) override;
 
  private:
+  friend class RootWindowController;
+
   WmShellMus* shell_;
   RootWindowController* root_window_controller_;
   base::ObserverList<WmRootWindowControllerObserver> observers_;