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

ash/accelerators/accelerator_controller.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 <algorithm>
 #include <cmath>
 #include <string>
 
@@ skipping 425 matching lines @@
     case NEW_TAB:
       if (key_code == ui::VKEY_T && shell->delegate())
         shell->delegate()->RecordUserMetricsAction(UMA_ACCEL_NEWTAB_T);
       return HandleNewTab();
     case NEW_WINDOW:
       return HandleNewWindow(false /* is_incognito */);
     case RESTORE_TAB:
       return HandleRestoreTab();
     case TAKE_SCREENSHOT:
     case TAKE_SCREENSHOT_BY_PRTSCN_KEY:
-      if (screenshot_delegate_.get()) {
+      if (screenshot_delegate_.get() &&
+          screenshot_delegate_->CanTakeScreenshot()) {
         Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
         for (size_t i = 0; i < root_windows.size(); ++i)
           screenshot_delegate_->HandleTakeScreenshot(root_windows[i]);
       }
       // Return true to prevent propagation of the key event.
       return true;
     case TAKE_PARTIAL_SCREENSHOT:
       if (screenshot_delegate_.get())
         ash::Shell::GetInstance()->delegate()->
             StartPartialScreenshot(screenshot_delegate_.get());
@@ skipping 279 matching lines @@
     // Then set this one as active.
     Shell::GetInstance()->launcher()->ActivateLauncherItem(found_index);
   }
 }
 
 bool AcceleratorController::CanHandleAccelerators() const {
   return true;
 }
 
 }  // namespace ash