Rename GetRootWindow() -> GetPrimaryRootWindow()

ash/shell.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 ASH_SHELL_H_
 #define ASH_SHELL_H_
 #pragma once
 
 #include <utility>
 #include <vector>
@@ skipping 115 matching lines @@
   static Shell* CreateInstance(ShellDelegate* delegate);
 
   // Should never be called before |CreateInstance()|.
   static Shell* GetInstance();
 
   // Returns true if the ash shell has been instantiated.
   static bool HasInstance();
 
   static void DeleteInstance();
 
-  // Gets the singleton RootWindow used by the Shell.
-  static aura::RootWindow* GetRootWindow();
+  // Gets the primary RootWindow. The primary RootWindow is the root window
+  // that has a launcher.
+  static aura::RootWindow* GetPrimaryRootWindow();
 
   internal::RootWindowLayoutManager* root_window_layout() const {
     return root_window_layout_;
   }
 
   aura::Window* GetContainer(int container_id);
   const aura::Window* GetContainer(int container_id) const;
 
   // Adds or removes |filter| from the RootWindowEventFilter.
   void AddRootWindowEventFilter(aura::EventFilter* filter);
@@ skipping 250 matching lines @@
 
   // Used by ash/shell.
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_H_