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 85 matching lines @@
 const int64 kVisualFeedbackLayerDisplayTimeMs = 100;
 
 }  // namespace
 
 ScreenshotTaker::ScreenshotTaker() {
 }
 
 ScreenshotTaker::~ScreenshotTaker() {
 }
 
+void ScreenshotTaker::HandleTakeScreenshot(aura::Window* window) {
+  HandleTakePartialScreenshot(window, window->bounds());
+}
+
 void ScreenshotTaker::HandleTakePartialScreenshot(
     aura::Window* window, const gfx::Rect& rect) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
   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(
         ash::Shell::GetInstance()->delegate()->GetCurrentBrowserContext());
     screenshot_directory = download_prefs->DownloadPath();
   } else {
     if (!file_util::GetTempDir(&screenshot_directory)) {
       LOG(ERROR) << "Failed to find temporary directory.";
       return;
     }
   }
 
   bool use_24hour_clock = ShouldUse24HourClock();
 
   if (GrabWindowSnapshot(window, rect, &png_data->data())) {
+    last_screenshot_timestamp_ = base::Time::Now();
     DisplayVisualFeedback(rect);
     content::BrowserThread::PostTask(
         content::BrowserThread::FILE, FROM_HERE,
         base::Bind(&SaveScreenshot, screenshot_directory, use_24hour_clock,
                    png_data));
   } else {
     LOG(ERROR) << "Failed to grab the window screenshot";
   }
 }
 
-void ScreenshotTaker::HandleTakeScreenshot(aura::Window* window) {
-  HandleTakePartialScreenshot(window, window->bounds());
+bool ScreenshotTaker::CanTakeScreenshot() {
+  return last_screenshot_timestamp_.is_null() ||
+      base::Time::Now() - last_screenshot_timestamp_ >
+      base::TimeDelta::FromMilliseconds(
+          kScreenshotMinimumIntervalInMS);
 }
 
 void ScreenshotTaker::CloseVisualFeedbackLayer() {
   visual_feedback_layer_.reset();
 }
 
 void ScreenshotTaker::DisplayVisualFeedback(const gfx::Rect& rect) {
   visual_feedback_layer_.reset(new ui::Layer(ui::LAYER_SOLID_COLOR));
   visual_feedback_layer_->SetColor(SK_ColorWHITE);
   visual_feedback_layer_->SetOpacity(kVisualFeedbackLayerOpacity);
   visual_feedback_layer_->SetBounds(rect);
 
   ui::Layer* parent = ash::Shell::GetContainer(
       ash::Shell::GetActiveRootWindow(),
       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));
 }