[gtk] Close zoom bubble immediately when window is closed to avoid orphaned

chrome/browser/ui/gtk/zoom_bubble_gtk.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 "chrome/browser/ui/gtk/zoom_bubble_gtk.h"
 
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/gtk/gtk_theme_service.h"
@@ skipping 30 matching lines @@
   // |auto_close|, the bubble can be reused and only the label text needs to
   // be updated.
   if (g_bubble &&
       g_bubble->auto_close_ == auto_close &&
       g_bubble->bubble_->anchor_widget() == anchor) {
     g_bubble->Refresh();
   } else {
     // If the bubble is already showing but its |auto_close_| value is not equal
     // to |auto_close|, the bubble's focus properties must change, so the
     // current bubble must be closed and a new one created.
-    if (g_bubble)
-      g_bubble->Close();
+    Close();
+    DCHECK(!g_bubble);
 
     g_bubble = new ZoomBubbleGtk(anchor, tab_contents, auto_close);
   }
 }
 
 // static
 void ZoomBubbleGtk::Close() {
   if (g_bubble)
     g_bubble->CloseBubble();
 }
@@ skipping 135 matching lines @@
   StopTimerIfNecessary();
   return FALSE;
 }
 
 gboolean ZoomBubbleGtk::OnMouseLeave(GtkWidget* widget,
                                      GdkEventCrossing* event) {
   mouse_inside_ = false;
   StartTimerIfNecessary();
   return FALSE;
 }