Brushes up the code of screenshot filename.

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 423 matching lines @@
         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() &&
           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]);
+        screenshot_delegate_->HandleTakeScreenshotForAllRootWindows();
       }
       // Return true to prevent propagation of the key event.
       return true;
     case TAKE_PARTIAL_SCREENSHOT:
       if (screenshot_delegate_.get()) {
         ash::PartialScreenshotView::StartPartialScreenshot(
             screenshot_delegate_.get());
       }
       // Return true to prevent propagation of the key event because
       // this key combination is reserved for partial screenshot.
@@ skipping 289 matching lines @@
     accelerators_.insert(
         std::make_pair(accelerator, accelerators[i].action));
   }
 }
 
 bool AcceleratorController::CanHandleAccelerators() const {
   return true;
 }
 
 }  // namespace ash