Change the order of visual feedback effect and grabbing screenshot.

chrome/browser/ui/views/ash/screenshot_taker.cc

Index: chrome/browser/ui/views/ash/screenshot_taker.cc
diff --git a/chrome/browser/ui/views/ash/screenshot_taker.cc b/chrome/browser/ui/views/ash/screenshot_taker.cc
index b5f78289ca467c3f33281d786ba65ebca508d913..1657409ab7d4491df66b307632e0465e2504d18d 100644
--- a/chrome/browser/ui/views/ash/screenshot_taker.cc
+++ b/chrome/browser/ui/views/ash/screenshot_taker.cc
@@ -66,23 +66,8 @@ void SaveScreenshot(bool is_logged_in,
   }
 }
 
-// How opaque should the layer that we flash onscreen to provide visual
-// feedback after the screenshot is taken be?
-const float kVisualFeedbackLayerOpacity = 0.25f;
-
-// How long should the visual feedback layer be displayed?
-const int64 kVisualFeedbackLayerDisplayTimeMs = 100;
-
-}  // namespace
-
-ScreenshotTaker::ScreenshotTaker() {
-}
-
-ScreenshotTaker::~ScreenshotTaker() {
-}
-
-void ScreenshotTaker::HandleTakePartialScreenshot(
-    aura::Window* window, const gfx::Rect& rect) {
+// Actually takes the screenshot.
+void TakeScreenshot(aura::Window* window, const gfx::Rect& rect) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
   scoped_refptr<RefCountedBytes> png_data(new RefCountedBytes);
@@ -93,7 +78,6 @@ void ScreenshotTaker::HandleTakePartialScreenshot(
 #endif
 
   if (browser::GrabWindowSnapshot(window, &png_data->data(), rect)) {
-    DisplayVisualFeedback(rect);
     content::BrowserThread::PostTask(
         content::BrowserThread::FILE, FROM_HERE,
         base::Bind(&SaveScreenshot, is_logged_in, png_data));
@@ -102,15 +86,42 @@ void ScreenshotTaker::HandleTakePartialScreenshot(
   }
 }
 
+// How opaque should the layer that we flash onscreen to provide visual
+// feedback after the screenshot is taken be?
+const float kVisualFeedbackLayerOpacity = 0.25f;
+
+// How long should the visual feedback layer be displayed?
+const int64 kVisualFeedbackLayerDisplayTimeMs = 100;
+
+}  // namespace
+
+ScreenshotTaker::ScreenshotTaker() {
+}
+
+ScreenshotTaker::~ScreenshotTaker() {
+}
+
+void ScreenshotTaker::HandleTakePartialScreenshot(aura::Window* window,
+                                                  const gfx::Rect& rect) {
+  // browser::GrabWindowSnapshot takes ~100msec and making visual feedback after
+  // that leads noticeable delay.  To prevent this delay, we just make the
+  // visual effect first, and then run the actual task of taking screenshot.
+  DisplayVisualFeedback(
+      rect,
+      base::Bind(&TakeScreenshot, base::Unretained(window), rect));
+}
+
 void ScreenshotTaker::HandleTakeScreenshot(aura::Window* window) {
   HandleTakePartialScreenshot(window, window->bounds());
 }
 
-void ScreenshotTaker::CloseVisualFeedbackLayer() {
+void ScreenshotTaker::CloseVisualFeedbackLayer(const base::Closure& task) {
   visual_feedback_layer_.reset();
+  task.Run();
 }
 
-void ScreenshotTaker::DisplayVisualFeedback(const gfx::Rect& rect) {
+void ScreenshotTaker::DisplayVisualFeedback(const gfx::Rect& rect,
+                                            const base::Closure& task) {
   visual_feedback_layer_.reset(new ui::Layer(ui::Layer::LAYER_SOLID_COLOR));
   visual_feedback_layer_->SetColor(SK_ColorWHITE);
   visual_feedback_layer_->SetOpacity(kVisualFeedbackLayerOpacity);
@@ -124,6 +135,7 @@ void ScreenshotTaker::DisplayVisualFeedback(const gfx::Rect& rect) {
   MessageLoopForUI::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ScreenshotTaker::CloseVisualFeedbackLayer,
-                 base::Unretained(this)),
+                 base::Unretained(this),
+                 task),
       base::TimeDelta::FromMilliseconds(kVisualFeedbackLayerDisplayTimeMs));
 }