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

R=sky@chromium.org
BUG=135535
TEST=manually checked the behavior by keep pressing Ctrl-F5 on lumpy


Review URL: https://chromiumcodereview.appspot.com/10802046

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148062 0039d316-1c4b-4281-b951-d872f2087c98

ash/accelerators/accelerator_controller.cc

@@ -443,7 +443,8 @@ bool AcceleratorController::PerformAction(int action,
       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]);

ash/accelerators/accelerator_controller_unittest.cc

@@ -81,6 +81,10 @@ class DummyScreenshotDelegate : public ScreenshotDelegate {
     ++handle_take_partial_screenshot_count_;
   }
 
+  virtual bool CanTakeScreenshot() OVERRIDE {
+    return true;
+  }
+
   int handle_take_screenshot_count() const {
     return handle_take_screenshot_count_;
   }

ash/accelerators/accelerator_filter_unittest.cc

@@ -40,6 +40,10 @@ class DummyScreenshotDelegate : public ScreenshotDelegate {
     // Do nothing because it's not tested yet.
   }
 
+  virtual bool CanTakeScreenshot() OVERRIDE {
+    return true;
+  }
+
   int handle_take_screenshot_count() const {
     return handle_take_screenshot_count_;
   }

ash/screenshot_delegate.h

@@ -29,6 +29,9 @@ class ScreenshotDelegate {
   // window.
   virtual void HandleTakePartialScreenshot(
       aura::Window* window, const gfx::Rect& rect) = 0;
+
+  // Returns true if the system is ready to take screenshot.
+  virtual bool CanTakeScreenshot() = 0;
 };
 }  // namespace ash
 

chrome/browser/ui/ash/screenshot_taker.cc

@@ -33,6 +33,8 @@
 #endif
 
 namespace {
+const int kScreenshotMinimumIntervalInMS = 500;
+
 bool ShouldUse24HourClock() {
 #if defined(OS_CHROMEOS)
   Profile* profile = ProfileManager::GetDefaultProfileOrOffTheRecord();
@@ -138,6 +140,10 @@ 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));
@@ -164,6 +170,7 @@ void ScreenshotTaker::HandleTakePartialScreenshot(
   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,
@@ -174,8 +181,11 @@ void ScreenshotTaker::HandleTakePartialScreenshot(
   }
 }
 
-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() {

chrome/browser/ui/ash/screenshot_taker.h

@@ -8,6 +8,7 @@
 #include "ash/screenshot_delegate.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/time.h"
 #include "ui/compositor/layer.h"
 
 namespace aura {
@@ -21,8 +22,9 @@ class ScreenshotTaker : public ash::ScreenshotDelegate {
 
   // Overridden from ash::ScreenshotDelegate:
   virtual void HandleTakeScreenshot(aura::Window* window) OVERRIDE;
-  virtual void HandleTakePartialScreenshot(
-      aura::Window* window, const gfx::Rect& rect) OVERRIDE;
+  virtual void HandleTakePartialScreenshot(aura::Window* window,
+                                           const gfx::Rect& rect) OVERRIDE;
+  virtual bool CanTakeScreenshot() OVERRIDE;
 
  private:
   // Flashes the screen to provide visual feedback that a screenshot has
@@ -32,6 +34,11 @@ class ScreenshotTaker : public ash::ScreenshotDelegate {
   // Closes the visual feedback layer.
   void CloseVisualFeedbackLayer();
 
+  // The timestamp when the screenshot task was issued last time.
+  base::Time last_screenshot_timestamp_;
+
+  // The flashing effect of the screen for the visual feedback when taking a
+  // screenshot.
   scoped_ptr<ui::Layer> visual_feedback_layer_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenshotTaker);