Ignores screenshot taking invocations if it's too close to the previous one.

ash/accelerators/accelerator_controller_unittest.cc

 // 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.
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/accelerators/accelerator_table.h"
 #include "ash/caps_lock_delegate.h"
 #include "ash/ime_control_delegate.h"
 #include "ash/screenshot_delegate.h"
 #include "ash/shell.h"
@@ skipping 63 matching lines @@
   virtual void HandleTakeScreenshot(aura::Window* window) OVERRIDE {
     if (window != NULL)
       ++handle_take_screenshot_count_;
   }
 
   virtual void HandleTakePartialScreenshot(
       aura::Window* window, const gfx::Rect& rect) OVERRIDE {
     ++handle_take_partial_screenshot_count_;
   }
 
+  virtual bool CanTakeScreenshot() OVERRIDE {
+    return true;
+  }
+
   int handle_take_screenshot_count() const {
     return handle_take_screenshot_count_;
   }
 
   int handle_take_partial_screenshot_count() const {
     return handle_take_partial_screenshot_count_;
   }
 
  private:
   int handle_take_screenshot_count_;
@@ skipping 886 matching lines @@
   EXPECT_FALSE(GetController()->IsReservedAccelerator(
       ui::Accelerator(ui::VKEY_PRINT, ui::EF_NONE)));
   EXPECT_FALSE(GetController()->IsReservedAccelerator(
       ui::Accelerator(ui::VKEY_TAB, ui::EF_NONE)));
   EXPECT_FALSE(GetController()->IsReservedAccelerator(
       ui::Accelerator(ui::VKEY_A, ui::EF_NONE)));
 }
 
 }  // namespace test
 }  // namespace ash