Fixed a few data races on reference counters.

chrome/browser/extensions/user_script_master.h

 // Copyright (c) 2008 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_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_
 #define CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_
 
 #include <vector>
 
 #include "base/directory_watcher.h"
 #include "base/file_path.h"
 #include "base/scoped_ptr.h"
 #include "base/shared_memory.h"
 #include "chrome/common/extensions/user_script.h"
 #include "chrome/common/notification_registrar.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 class MessageLoop;
 namespace base {
 class StringPiece;
 }
 
 // Manages a segment of shared memory that contains the user scripts the user
 // has installed.  Lives on the UI thread.
-class UserScriptMaster : public base::RefCounted<UserScriptMaster>,
+class UserScriptMaster : public base::RefCountedThreadSafe<UserScriptMaster>,

[Aaron Boodman, 2009/09/17 22:59:34]

Does this class actually get called on multiple threads? It seems like it is
only called on the UI thread.

                          public DirectoryWatcher::Delegate,
                          public NotificationObserver {
  public:
   // For testability, the constructor takes the MessageLoop to run the
   // script-reloading worker on as well as the path the scripts live in.
   // These are normally the file thread and a directory inside the profile.
   UserScriptMaster(MessageLoop* worker, const FilePath& script_dir);
   virtual ~UserScriptMaster();
 
   // Add a watched directory. All scripts will be reloaded when any file in
@@ skipping 26 matching lines @@
   FRIEND_TEST(UserScriptMasterTest, Parse5);
   FRIEND_TEST(UserScriptMasterTest, Parse6);
 
   // We reload user scripts on the file thread to prevent blocking the UI.
   // ScriptReloader lives on the file thread and does the reload
   // work, and then sends a message back to its master with a new SharedMemory*.
   // ScriptReloader is the worker that manages running the script scan
   // on the file thread. It must be created on, and its public API must only be
   // called from, the master's thread.
   class ScriptReloader
       : public base::RefCounted<UserScriptMaster::ScriptReloader> {

[Aaron Boodman, 2009/09/17 22:59:34]

It seems like this guy needs to be base::RefCountedThreadSafe.

    public:
     // Parses the includes out of |script| and returns them in |includes|.
     static bool ParseMetadataHeader(const base::StringPiece& script_text,
                                     UserScript* script);
 
     static void LoadScriptsFromDirectory(const FilePath& script_dir,
                                          UserScriptList* result);
 
     explicit ScriptReloader(UserScriptMaster* master);
 
@@ skipping 73 matching lines @@
 
   // If the script directory is modified while we're rescanning it, we note
   // that we're currently mid-scan and then start over again once the scan
   // finishes.  This boolean tracks whether another scan is pending.
   bool pending_scan_;
 
   DISALLOW_COPY_AND_ASSIGN(UserScriptMaster);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_