Fix some grammatical errors in webkit/

webkit/appcache/appcache_service.h

 // Copyright (c) 2011 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 WEBKIT_APPCACHE_APPCACHE_SERVICE_H_
 #define WEBKIT_APPCACHE_APPCACHE_SERVICE_H_
 
 #include <map>
 #include <set>
 
@@ skipping 32 matching lines @@
 struct APPCACHE_EXPORT AppCacheInfoCollection
     : public base::RefCountedThreadSafe<AppCacheInfoCollection> {
   AppCacheInfoCollection();
   virtual ~AppCacheInfoCollection();
 
   std::map<GURL, AppCacheInfoVector> infos_by_origin;
 };
 
 // Class that manages the application cache service. Sends notifications
 // to many frontends.  One instance per user-profile. Each instance has
-// exclusive access to it's cache_directory on disk.
+// exclusive access to its cache_directory on disk.
 class APPCACHE_EXPORT AppCacheService {
  public:
   // If not using quota management, the proxy may be NULL.
   explicit AppCacheService(quota::QuotaManagerProxy* quota_manager_proxy);
   virtual ~AppCacheService();
 
   void Initialize(const FilePath& cache_directory,
                   base::MessageLoopProxy* db_thread,
                   base::MessageLoopProxy* cache_thread);
 
@@ skipping 116 matching lines @@
   bool clear_local_state_on_exit_;
   // If true, nothing (not even session-only data) should be deleted on exit.
   bool save_session_state_;
 
   DISALLOW_COPY_AND_ASSIGN(AppCacheService);
 };
 
 }  // namespace appcache
 
 #endif  // WEBKIT_APPCACHE_APPCACHE_SERVICE_H_