Use copies of canned browsing data helpers to populate the cookies tree model.

chrome/browser/browsing_data_database_helper.h

Index: chrome/browser/browsing_data_database_helper.h
diff --git a/chrome/browser/browsing_data_database_helper.h b/chrome/browser/browsing_data_database_helper.h
index 2d870ee1b29e14e2e3f0a4f391b46cf6a3ba1a1d..ac59f85263d5d5290f29de120879c14e409eff92 100644
--- a/chrome/browser/browsing_data_database_helper.h
+++ b/chrome/browser/browsing_data_database_helper.h
@@ -109,6 +109,11 @@ class CannedBrowsingDataDatabaseHelper : public BrowsingDataDatabaseHelper {
  public:
   explicit CannedBrowsingDataDatabaseHelper(Profile* profile);
 
+  // Return a copy of the database helper. Only one consumer can use the
+  // StartFetching method at a time, so we need to create a copy of the helper
+  // everytime we instantiate a cookies tree model for it.
+  CannedBrowsingDataDatabaseHelper* Clone();
+
   // Add a database to the set of canned databases that is returned by this
   // helper.
   void AddDatabase(const GURL& origin,
@@ -150,6 +155,8 @@ class CannedBrowsingDataDatabaseHelper : public BrowsingDataDatabaseHelper {
   // This may mutate on WEBKIT and UI threads.
   std::vector<PendingDatabaseInfo> pending_database_info_;
 
+  Profile* profile_;
+
   DISALLOW_COPY_AND_ASSIGN(CannedBrowsingDataDatabaseHelper);
 };