[Mac] Fix for zoom decoration regression

chrome/browser/ui/cocoa/location_bar/zoom_decoration.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/location_bar/zoom_decoration.h"
 
 #include "base/i18n/number_formatting.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
@@ skipping 21 matching lines @@
                                        bool default_zoom_changed,
                                        bool location_bar_is_dark) {
   if (!ShouldShowDecoration()) {
     if (!IsVisible() && !bubble_)
       return false;
 
     HideUI();
     return true;
   }
 
+  BOOL old_visibility = IsVisible();
   SetVisible(ShouldShowDecoration() && !zoom_controller->IsAtDefaultZoom());
 
   base::string16 zoom_percent =
       base::FormatPercent(zoom_controller->GetZoomPercent());
   // There is no icon at the default zoom factor (100%), so don't display a
   // tooltip either.
   NSString* tooltip_string =
       zoom_controller->IsAtDefaultZoom()
           ? @""
           : l10n_util::GetNSStringF(IDS_TOOLTIP_ZOOM, zoom_percent);
 
-  if ([tooltip_ isEqualToString:tooltip_string] && !default_zoom_changed)
+  if ([tooltip_ isEqualToString:tooltip_string] && !default_zoom_changed &&
+      old_visibility == IsVisible()) {
     return false;
+  }
 
   UpdateUI(zoom_controller, tooltip_string, location_bar_is_dark);
   return true;
 }
 
 void ZoomDecoration::ShowBubble(BOOL auto_close) {
   if (bubble_) {
     bubble_.delegate = nil;
     [[bubble_.window parentWindow] removeChildWindow:bubble_.window];
     [bubble_.window orderOut:nil];
@@ skipping 100 matching lines @@
   // closed the decoration can be hidden.
   if (IsAtDefaultZoom() && IsVisible()) {
     SetVisible(false);
     owner_->OnDecorationsChanged();
   }
 }
 
 const gfx::VectorIcon* ZoomDecoration::GetMaterialVectorIcon() const {
   return vector_icon_;
 }