Disabled DesktopMediaPickerViewsTest.DoneCallbackCalledOnOkButtonPressed test on Windows

This test has been flaky for a couple of weeks now. Disabling on
Windows platform until that can be corrected.

TBR=qiangchen@chromium.org
BUG=644614

Review-Url: https://codereview.chromium.org/2346253003
Cr-Commit-Position: refs/heads/master@{#419472}

chrome/browser/ui/views/desktop_capture/desktop_media_picker_views_unittest.cc

@@ -99,7 +99,14 @@ TEST_F(DesktopMediaPickerViewsTest, DoneCallbackCalledWhenWindowClosed) {
   base::RunLoop().RunUntilIdle();
 }
 
-TEST_F(DesktopMediaPickerViewsTest, DoneCallbackCalledOnOkButtonPressed) {
+// Flaky on Windows. https://crbug.com/644614
+#if defined(OS_WIN)
+#define MAYBE_DoneCallbackCalledOnOkButtonPressed DISABLED_DoneCallbackCalledOnOkButtonPressed
+#else
+#define MAYBE_DoneCallbackCalledOnOkButtonPressed DoneCallbackCalledOnOkButtonPressed
+#endif
+
+TEST_F(DesktopMediaPickerViewsTest, MAYBE_DoneCallbackCalledOnOkButtonPressed) {
   const DesktopMediaID kFakeId(DesktopMediaID::TYPE_WINDOW, 222);
   EXPECT_CALL(*this, OnPickerDone(kFakeId));