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

chrome/browser/ui/ash/screenshot_taker.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 "chrome/browser/ui/ash/screenshot_taker.h"
 
 #include <climits>
 #include <string>
 
 #include "ash/shell.h"
@@ skipping 15 matching lines @@
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/login/user_manager.h"
 #endif
 
 namespace {
+const int kScreenshotMinimumIntervalInMS = 500;
+
 bool ShouldUse24HourClock() {
 #if defined(OS_CHROMEOS)
   Profile* profile = ProfileManager::GetDefaultProfileOrOffTheRecord();
   if (profile) {
     PrefService* pref_service = profile->GetPrefs();
     if (pref_service) {
       return pref_service->GetBoolean(prefs::kUse24HourClock);
     }
   }
 #endif
@@ skipping 89 matching lines @@
 ScreenshotTaker::ScreenshotTaker() {
 }
 
 ScreenshotTaker::~ScreenshotTaker() {
 }
 
 void ScreenshotTaker::HandleTakePartialScreenshot(
     aura::Window* window, const gfx::Rect& rect) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
+  aura::RootWindow* root_window = window->GetRootWindow();

[sky, 2012/07/20 16:13:31]

Do we really care about what root window this came from? Can't we have the time
apply to all?
If not, the map needs to be pruned when rootwindows are removed.

[Jun Mukai, 2012/07/20 17:07:32]

This method is invoked several times for a single Ctrl-F5 when multiple displays
are available.  see ash/accelerators/accelerator_controller.cc.  Possibly we can
check the timestamp in the accelerator_controller...

+  base::Time now = base::Time::Now();
+  std::map<aura::RootWindow*, base::Time>::const_iterator iter =
+      last_screenshot_timestamps_.find(root_window);
+  if (iter != last_screenshot_timestamps_.end()) {
+    base::Time last = iter->second;
+    // Ignore if the command is issued too closely to the last command.
+    if (now - last <= base::TimeDelta::FromMilliseconds(
+            kScreenshotMinimumIntervalInMS))
+      return;
+  }
+  last_screenshot_timestamps_[root_window] = now;
+
   scoped_refptr<base::RefCountedBytes> png_data(new base::RefCountedBytes);
 
   bool is_logged_in = true;
 #if defined(OS_CHROMEOS)
   is_logged_in = chromeos::UserManager::Get()->IsUserLoggedIn();
 #endif
 
   FilePath screenshot_directory;
   if (is_logged_in) {
     DownloadPrefs* download_prefs = DownloadPrefs::FromBrowserContext(
@@ skipping 38 matching lines @@
       ash::internal::kShellWindowId_OverlayContainer)->layer();
   parent->Add(visual_feedback_layer_.get());
   visual_feedback_layer_->SetVisible(true);
 
   MessageLoopForUI::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ScreenshotTaker::CloseVisualFeedbackLayer,
                  base::Unretained(this)),
       base::TimeDelta::FromMilliseconds(kVisualFeedbackLayerDisplayTimeMs));
 }