Fix partial screenshot/window screenshot when holding Alt+Tab.

ash/utility/screenshot_controller_unittest.cc

 // Copyright 2014 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 "ash/utility/screenshot_controller.h"
 
 #include "ash/display/cursor_window_controller.h"
 #include "ash/display/mouse_cursor_event_filter.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/screenshot_delegate.h"
@@ skipping 463 matching lines @@
   RunAllPendingInMessageLoop();
   EXPECT_FALSE(IsActive());
 
   StartWindowScreenshotSession();
   EXPECT_TRUE(IsActive());
   UpdateDisplay("400x400");
   RunAllPendingInMessageLoop();
   EXPECT_FALSE(IsActive());
 }
 
+// Windows that take capture can misbehave due to a screenshot session. Break
+// mouse capture when the screenshot session is over. See crbug.com/651939
+TEST_F(ScreenshotControllerTest, BreaksCapture) {
+  std::unique_ptr<aura::Window> window(
+      CreateSelectableWindow(gfx::Rect(100, 100, 100, 100)));
+  window->SetCapture();
+  EXPECT_TRUE(window->HasCapture());
+  StartWindowScreenshotSession();
+  EXPECT_TRUE(window->HasCapture());
+  Cancel();
+  EXPECT_FALSE(window->HasCapture());
+}
+
 }  // namespace ash