Only invoke WebKit methods in browsing data helpers on the WEBKIT thread.

chrome/browser/browsing_data_indexed_db_helper.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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 CHROME_BROWSER_BROWSING_DATA_INDEXED_DB_HELPER_H_
 #define CHROME_BROWSER_BROWSING_DATA_INDEXED_DB_HELPER_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/file_path.h"
 #include "base/ref_counted.h"
+#include "base/scoped_ptr.h"
+#include "base/synchronization/lock.h"
 #include "base/time.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/gurl.h"
 
 class Profile;
 
 // BrowsingDataIndexedDBHelper is an interface for classes dealing with
 // aggregating and deleting browsing data stored in indexed databases.  A
 // client of this class need to call StartFetching from the UI thread to
 // initiate the flow, and it'll be notified by the callback in its UI thread at
@@ skipping 69 matching lines @@
   // True if no indexed databases are currently stored.
   bool empty() const;
 
   // BrowsingDataIndexedDBHelper methods.
   virtual void StartFetching(
       Callback1<const std::vector<IndexedDBInfo>& >::Type* callback);
   virtual void CancelNotification() {}
   virtual void DeleteIndexedDBFile(const FilePath& file_path) {}
 
  private:
+  struct PendingIndexedDBInfo {
+    PendingIndexedDBInfo();
+    PendingIndexedDBInfo(const GURL& origin, const string16& description);
+    ~PendingIndexedDBInfo();
+
+    GURL origin;
+    string16 description;
+  };
+
   virtual ~CannedBrowsingDataIndexedDBHelper();
 
+  // Convert the pending indexed db info to indexed db info objects.
+  void ConvertPendingInfoInWebKitThread();

[bulach, 2011/02/22 22:34:01]

as above

+
+  void NotifyInUIThread();
+
   Profile* profile_;
 
+  // Lock to protect access to pending_indexed_db_info_;
+  mutable base::Lock lock_;
+
+  // This may mutate on WEBKIT and UI threads.
+  std::vector<PendingIndexedDBInfo> pending_indexed_db_info_;
+
+  // This only mutates on the WEBKIT thread.
   std::vector<IndexedDBInfo> indexed_db_info_;
 
+  // This only mutates on the UI thread.
+  scoped_ptr<Callback1<const std::vector<IndexedDBInfo>& >::Type >
+      completion_callback_;
+
+  // Indicates whether or not we're currently fetching information:
+  // it's true when StartFetching() is called in the UI thread, and it's reset
+  // after we notified the callback in the UI thread.
+  // This only mutates on the UI thread.
+  bool is_fetching_;
+
   DISALLOW_COPY_AND_ASSIGN(CannedBrowsingDataIndexedDBHelper);
 };
 
 #endif  // CHROME_BROWSER_BROWSING_DATA_INDEXED_DB_HELPER_H_