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

chrome/browser/ui/gtk/browser_titlebar.h

 // 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.
 //
 // A helper class that contains the gtk widgets that make up the titlebar.  The
 // titlebar consists of the tabstrip and if the custom chrome frame is turned
 // on, it includes the taller titlebar and minimize, restore, maximize, and
 // close buttons.
 
 #ifndef CHROME_BROWSER_UI_GTK_BROWSER_TITLEBAR_H_
@@ skipping 188 matching lines @@
 
   bool IsTypePanel();
 
   // Whether to display the avatar image.
   bool ShouldDisplayAvatar();
 
   // Returns true if the profile associated with this BrowserWindow is off the
   // record.
   bool IsOffTheRecord();
 
-  // Pointers to the browser window that owns us and it's GtkWindow.
+  // Pointers to the browser window that owns us and its GtkWindow.
   BrowserWindowGtk* browser_window_;
   GtkWindow* window_;
 
   // The container widget the holds the hbox which contains the whole titlebar.
   GtkWidget* container_;
 
   // The hbox that contains the whole titlebar.
   GtkWidget* container_hbox_;
 
   // VBoxes that holds the min/max/close buttons box and an optional padding
@@ skipping 70 matching lines @@
   // The avatar button.
   scoped_ptr<AvatarMenuButtonGtk> avatar_button_;
 
   // Theme provider for building buttons.
   ThemeServiceGtk* theme_service_;
 
   content::NotificationRegistrar registrar_;
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_BROWSER_TITLEBAR_H_