Fix some grammar in chrome/browser/ui/gtk/

chrome/browser/ui/gtk/extensions/extension_installed_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/extensions/extension_installed_bubble_gtk.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 144 matching lines @@
           toolbar->chevron() : NULL;
     }
   } else if (type_ == PAGE_ACTION) {
     LocationBarViewGtk* location_bar_view =
         browser_window->GetToolbar()->GetLocationBarView();
     location_bar_view->SetPreviewEnabledPageAction(extension_->page_action(),
                                                    true);  // preview_enabled
     reference_widget = location_bar_view->GetPageActionWidget(
         extension_->page_action());
     // glib delays recalculating layout, but we need reference_widget to know
-    // it's coordinates, so we force a check_resize here.
+    // its coordinates, so we force a check_resize here.
     gtk_container_check_resize(GTK_CONTAINER(
         browser_window->GetToolbar()->widget()));
     DCHECK(reference_widget);
   } else if (type_ == OMNIBOX_KEYWORD) {
     LocationBarViewGtk* location_bar_view =
         browser_window->GetToolbar()->GetLocationBarView();
     reference_widget = location_bar_view->location_entry_widget();
     DCHECK(reference_widget);
   }
 
@@ skipping 144 matching lines @@
   // on all references being cleared before it is destroyed.
   MessageLoopForUI::current()->PostTask(
       FROM_HERE,
       base::Bind(&ExtensionInstalledBubbleGtk::Close, this));
 }
 
 void ExtensionInstalledBubbleGtk::Close() {
   Release();  // Balanced in ctor.
   bubble_ = NULL;
 }