Fix uninitialized memory read in BubbleFrameViewTest.LayoutWithIcon.

Bug: 855584
Change-Id: I855566a5a9db76b68f2b182ca95b9617c81a6822
Reviewed-on: https://chromium-review.googlesource.com/1112476Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569755}

ui/views/bubble/bubble_frame_view_unittest.cc

@@ -789,6 +789,7 @@ TEST_F(BubbleFrameViewTest, LayoutWithIcon) {
   delegate.SetAnchorView(anchor.widget().GetContentsView());
   SkBitmap bitmap;
   bitmap.allocN32Pixels(20, 80);
+  bitmap.eraseColor(SK_ColorYELLOW);
   delegate.set_icon(gfx::ImageSkia::CreateFrom1xBitmap(bitmap));
 
   Widget* widget = BubbleDialogDelegateView::CreateBubble(&delegate);