Mark BubbleFrameViewTest.RemoveFootnoteView flaky on Mac

This patch marks BubbleFrameViewTest.RemoveFootnoteView flaky on Mac

TBR=mrefaat@chromium.org

Bug: 903003
Change-Id: I7028c038018bf1547b92a5c7fb19b5ddf65c3537
Reviewed-on: https://chromium-review.googlesource.com/c/1325590Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606328}

ui/views/bubble/bubble_frame_view_unittest.cc

@@ -139,7 +139,13 @@ TEST_F(BubbleFrameViewTest, GetBoundsForClientView) {
   EXPECT_EQ(insets.top() + margin_y, frame.GetBoundsForClientView().y());
 }
 
-TEST_F(BubbleFrameViewTest, RemoveFootnoteView) {
+// TODO(crbug.com/903003): We should not mark RemoveFootnoteView flaky.
+#if defined(OS_MACOSX)
+#define MAYBE_RemoveFootnoteView DISABLED_RemoveFootnoteView
+#else
+#define MAYBE_RemoveFootnoteView RemoveFootnoteView
+#endif
+TEST_F(BubbleFrameViewTest, MAYBE_RemoveFootnoteView) {
   TestBubbleFrameView frame(this);
   EXPECT_EQ(nullptr, frame.footnote_container_);
   View* footnote_dummy_view = new StaticSizedView(gfx::Size(200, 200));