Hide mouse cursor when screenshot is taking

ui/snapshot/screenshot_grabber.cc

Index: ui/snapshot/screenshot_grabber.cc
diff --git a/ui/snapshot/screenshot_grabber.cc b/ui/snapshot/screenshot_grabber.cc
index 4534a857b4beab8a5b77dc15a825a6098b8a508e..92a3e9e33de30843a05acf73e513b3d070042a3f 100644
--- a/ui/snapshot/screenshot_grabber.cc
+++ b/ui/snapshot/screenshot_grabber.cc
@@ -24,6 +24,7 @@
 #include "ui/snapshot/snapshot.h"
 
 #if defined(USE_AURA)
+#include "ui/aura/client/cursor_client.h"
 #include "ui/aura/window.h"
 #endif
 
@@ -108,6 +109,40 @@ void ScreenshotGrabberDelegate::PrepareFileAndRunOnBlockingPool(
       base::Bind(EnsureLocalDirectoryExists, path, callback_on_blocking_pool));
 }
 
+#if defined(USE_AURA)
+class ScreenshotGrabber::ScopedCursorHider {
+ public:
+  explicit ScopedCursorHider(aura::Window* window)
+      : window_(window), hid_cursor_(false) {
+    if (!window_->IsRootWindow())

[sky, 2016/07/22 16:14:44]

This should be a DCHECK.

[Qiang(Joe) Xu, 2016/07/22 20:15:26]

Done.

+      return;
+    aura::client::CursorClient* cursor_client =

[sky, 2016/07/22 16:14:44]

Having to have all these checks in both the constructor and destructor is ugly.
How about a static function that returns a std::unique_ptr<ScopedCursorHider>
only if appropriate? The constructor is private. That way you get rid of
hid_cursor.

[Qiang(Joe) Xu, 2016/07/22 20:15:26]

done. Thanks for suggestion.

+        aura::client::GetCursorClient(window_);
+    if (!cursor_client)
+      return;
+    cursor_client->HideCursor();
+    hid_cursor_ = true;
+  }
+  ~ScopedCursorHider() {
+    if (!window_->IsRootWindow())
+      return;
+    if (hid_cursor_) {
+      aura::client::CursorClient* cursor_client =
+          aura::client::GetCursorClient(window_);
+      if (!cursor_client)
+        return;
+      cursor_client->ShowCursor();
+    }
+  }
+
+ private:
+  aura::Window* window_;
+  bool hid_cursor_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedCursorHider);
+};
+#endif
+
 ScreenshotGrabber::ScreenshotGrabber(
     ScreenshotGrabberDelegate* client,
     scoped_refptr<base::TaskRunner> blocking_task_runner)
@@ -134,6 +169,8 @@ void ScreenshotGrabber::TakeScreenshot(gfx::NativeWindow window,
   aura::Window* aura_window = static_cast<aura::Window*>(window);
   is_partial = rect.size() != aura_window->bounds().size();
   window_identifier = aura_window->GetBoundsInScreen().ToString();
+
+  cursor_hider_.reset(new ScopedCursorHider(aura_window->GetRootWindow()));
 #endif
   ui::GrabWindowSnapshotAsync(
       window, rect, blocking_task_runner_,
@@ -152,6 +189,9 @@ void ScreenshotGrabber::NotifyScreenshotCompleted(
     ScreenshotGrabberObserver::Result screenshot_result,
     const base::FilePath& screenshot_path) {
   DCHECK(base::MessageLoopForUI::IsCurrent());
+#if defined(USE_AURA)
+  cursor_hider_.reset();
+#endif
   FOR_EACH_OBSERVER(ScreenshotGrabberObserver, observers_,
                     OnScreenshotCompleted(screenshot_result, screenshot_path));
 }