Fix regression where extension action icons may not be displayed properly

A BrowserActionView can set its image view for the first time in UpdateState(),
but UpdateState() only called SchedulePaint(), and not Layout() (which is
necessary for the image). Coincidentally, with all the Layout()s called on
BrowserActionsContainer, this only manifested itself in Windows 8 Metro Mode
(likely because race conditions caused the image to be updated after all calls
to Layout()).

BUG=409782

Review URL: https://codereview.chromium.org/608013002

Cr-Commit-Position: refs/heads/master@{#297069}

chrome/browser/ui/views/toolbar/browser_action_view.cc

@@ -154,6 +154,7 @@ void BrowserActionView::UpdateState() {
   SetTooltipText(name);
   SetAccessibleName(name);
 
+  Layout();  // We need to layout since we may have added an icon as a result.
   SchedulePaint();
 }