Makes the visual feedback for taking screenshot.

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

Index: chrome/browser/ui/views/aura/screenshot_taker.cc
diff --git a/chrome/browser/ui/views/aura/screenshot_taker.cc b/chrome/browser/ui/views/aura/screenshot_taker.cc
index c004e9c736fb66c4022d03da8cd7c0549332872e..6ee4169c3df9bae87bb17374f38706fa8727ab02 100644
--- a/chrome/browser/ui/views/aura/screenshot_taker.cc
+++ b/chrome/browser/ui/views/aura/screenshot_taker.cc
@@ -6,6 +6,8 @@
 
 #include <string>
 
+#include "ash/shell.h"
+#include "ash/shell_window_ids.h"
 #include "base/bind.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ -17,6 +19,7 @@
 #include "chrome/browser/ui/window_snapshot/window_snapshot.h"
 #include "content/public/browser/browser_thread.h"
 #include "ui/aura/window.h"
+#include "ui/gfx/compositor/layer.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/login/user_manager.h"
@@ -64,6 +67,37 @@ 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 unsigned char kVisualFeedbackWindowOpacity = 64;

[Daniel Erat, 2012/02/24 00:48:46]

nit: s/Window/Layer/ in variable name

[Jun Mukai, 2012/02/24 02:24:55]

Done.

+
+// How long should the visual feedback window be displayed?
+const uint64_t kVisualFeedbackWindowDisplayTimeMs = 100;

[Daniel Erat, 2012/02/24 00:48:46]

s/Window/Layer/

[Jun Mukai, 2012/02/24 02:24:55]

Done.

+
+void CloseFeedbackLayer(ui::Layer* layer) {
+  DCHECK(layer);
+  layer->SetVisible(false);

[Daniel Erat, 2012/02/24 00:48:46]

nit: unneeded; deleting it makes it invisible :-)

[Jun Mukai, 2012/02/24 02:24:55]

Done.

+  delete layer;
+}
+
+// Flashes the screen to provide visual feedback that a screenshot has
+// been taken.
+void DisplayVisualFeedback(const gfx::Rect& rect) {
+  scoped_ptr<ui::Layer> layer(new ui::Layer(ui::Layer::LAYER_SOLID_COLOR));
+  layer->SetColor(SkColorSetA(SK_ColorWHITE, kVisualFeedbackWindowOpacity));
+  layer->SetBounds(rect);
+
+  ui::Layer* parent = ash::Shell::GetInstance()->GetContainer(
+      ash::internal::kShellWindowId_OverlayContainer)->layer();
+  parent->Add(layer.get());
+  layer->SetVisible(true);
+
+  MessageLoopForUI::current()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&CloseFeedbackLayer, base::Unretained(layer.release())),

[Daniel Erat, 2012/02/24 00:48:46]

i meant that you could make these functions instead be private methods of
ScreenshotTaker.  create a scoped_ptr<ui::Layer> named something like
ScreenshotTaker::visual_feedback_layer_ and make CloseFeedbackLayer() take no
parameters and just call visual_feedback_layer_.reset();

[Jun Mukai, 2012/02/24 02:24:55]

Ah, thank you for the explanation.  Done.

+      kVisualFeedbackWindowDisplayTimeMs);
+}
+
 }  // namespace
 
 ScreenshotTaker::ScreenshotTaker() {
@@ -81,6 +115,7 @@ 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));