Fix some grammar in app_mode_common.h

chrome/common/mac/app_mode_common.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.
 
 #ifndef CHROME_COMMON_MAC_APP_MODE_COMMON_H_
 #define CHROME_COMMON_MAC_APP_MODE_COMMON_H_
 #pragma once
 
 #import <Foundation/Foundation.h>
 
@@ skipping 17 matching lines @@
 
 // Key for the app's URL.
 extern NSString* const kCrAppModeShortcutURLKey;
 
 // Key for the app user data directory.
 extern NSString* const kCrAppModeUserDataDirKey;
 
 // Key for the app's extension path.
 extern NSString* const kCrAppModeExtensionPathKey;
 
-// When the Chrome browser is run, it stores it's location in the defaults
+// When the Chrome browser is run, it stores its location in the defaults
 // system using this key.
 extern NSString* const kLastRunAppBundlePathPrefsKey;
 
 // Placeholders used in the app mode loader bundle' Info.plist:
 extern NSString* const kShortcutIdPlaceholder; // Extension shortcut ID.
 extern NSString* const kShortcutNamePlaceholder; // Extension name.
 extern NSString* const kShortcutURLPlaceholder;
 // Bundle ID of the Chrome browser bundle.
 extern NSString* const kShortcutBrowserBundleIDPlaceholder;
 
@@ skipping 44 matching lines @@
   // Path to the app's user data directory.
   FilePath user_data_dir;
 
   // Path to the app's extension.
   FilePath extension_path;
 };
 
 }  // namespace app_mode
 
 #endif  // CHROME_COMMON_MAC_APP_MODE_COMMON_H_