Removal of unnecessary views:: and fix comment

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <X11/extensions/shape.h>
@@ skipping 58 matching lines @@
   gfx::Rect GetX11RootWindowOuterBounds() const;
 
   // Returns the window shape if the window is not rectangular. Returns NULL
   // otherwise.
   ::Region GetWindowShape() const;
 
   // Called by X11DesktopHandler to notify us that the native windowing system
   // has changed our activation.
   void HandleNativeWidgetActivationChanged(bool active);
 
-  void AddObserver(views::DesktopWindowTreeHostObserverX11* observer);
-  void RemoveObserver(views::DesktopWindowTreeHostObserverX11* observer);
+  void AddObserver(DesktopWindowTreeHostObserverX11* observer);
+  void RemoveObserver(DesktopWindowTreeHostObserverX11* observer);
 
   // Swaps the current handler for events in the non client view with |handler|.
   void SwapNonClientEventHandler(std::unique_ptr<ui::EventHandler> handler);
 
   // Runs the |func| callback for each content-window, and deallocates the
   // internal list of open windows.
   static void CleanUpWindowList(void (*func)(aura::Window* window));
 
  protected:
   // Overridden from DesktopWindowTreeHost:
@@ skipping 270 matching lines @@
   base::CancelableCallback<void()> delayed_resize_task_;
 
   base::WeakPtrFactory<DesktopWindowTreeHostX11> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopWindowTreeHostX11);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_