Move non-browser specific ScreenshotTaker code to ui/snapshot.

ash/screenshot_delegate.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_SCREENSHOT_DELEGATE_H_
 #define ASH_SCREENSHOT_DELEGATE_H_
 
 namespace aura {
 class Window;
 }  // namespace aura
@@ skipping 14 matching lines @@
   virtual void HandleTakeScreenshotForAllRootWindows() = 0;
 
   // The actual task of taking a partial screenshot for the given
   // window.
   virtual void HandleTakePartialScreenshot(
       aura::Window* window, const gfx::Rect& rect) = 0;
 
   // Returns true if the system is ready to take screenshot.
   virtual bool CanTakeScreenshot() = 0;
 };
-}  // namespace ash
+
+}  // namespace
 
 #endif  // ASH_SCREENSHOT_DELEGATE_H_