[gtk] fix zoom bubble showing up on wrong window

content/browser/web_contents/web_contents_impl.cc

 // 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.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 1815 matching lines @@
     NavigationEntry* active_entry = GetController().GetActiveEntry();
     // Since zoom map is updated using rewritten URL, use rewritten URL
     // to get the zoom level.
     url = active_entry ? active_entry->GetURL() : GURL::EmptyGURL();
     zoom_level = zoom_map->GetZoomLevel(net::GetHostOrSpecFromURL(url));
   }
   return zoom_level;
 }
 
 int WebContentsImpl::GetZoomPercent(bool* enable_increment,
-                                    bool* enable_decrement) {
+                                    bool* enable_decrement) const {
   *enable_decrement = *enable_increment = false;
   // Calculate the zoom percent from the factor. Round up to the nearest whole
   // number.
   int percent = static_cast<int>(
       WebKit::WebView::zoomLevelToZoomFactor(GetZoomLevel()) * 100 + 0.5);
   *enable_decrement = percent > minimum_zoom_percent_;
   *enable_increment = percent < maximum_zoom_percent_;
   return percent;
 }
 
@@ skipping 1546 matching lines @@
   }
 }
 
 content::BrowserPluginGuest* WebContentsImpl::GetBrowserPluginGuest() {
   return browser_plugin_guest_.get();
 }
 
 content::BrowserPluginEmbedder* WebContentsImpl::GetBrowserPluginEmbedder() {
   return browser_plugin_embedder_.get();
 }