[Mac] Implement LocationBarViewMac::UpdateLocationBarVisibility()

chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h

Index: chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h
diff --git a/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h b/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h
index 1459ea60f5679c23a6dac863aa92af47f8127bf6..f8952f8632c0937e5a4cacbffc4fefc2e7a5e085 100644
--- a/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h
+++ b/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h
@@ -266,6 +266,10 @@ class LocationBarViewMac : public LocationBar,
   // Used to change the visibility of the star decoration.
   BooleanPrefMember edit_bookmarks_enabled_;
 
+  // Records whether the location bar is currently visible. Used to gate the
+  // number of calls to the BWC to change the visibility (and relayout).
+  bool visible_;
+
   // Used to schedule a task for the first run info bubble.
   base::WeakPtrFactory<LocationBarViewMac> weak_ptr_factory_;