Persist sessionStorage on disk.

chrome/browser/sessions/session_restore.cc

 // 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.
 
 #include "chrome/browser/sessions/session_restore.h"
 
 #include <algorithm>
 #include <list>
 #include <set>
 #include <string>
@@ skipping 715 matching lines @@
     base::TimeDelta time_to_process_sessions =
         base::TimeTicks::Now() - restore_started_;
     UMA_HISTOGRAM_CUSTOM_TIMES(
         "SessionRestore.TimeToProcessSessions",
         time_to_process_sessions,
         base::TimeDelta::FromMilliseconds(10),
         base::TimeDelta::FromSeconds(1000),
         100);
 
     if (windows->empty()) {
-      // Restore was unsuccessful.
+      // Restore was unsuccessful. The DOM storage system can also delete its
+      // data, since no session restore will happen at a later point in time.
+      content::DOMStorageContext* dom_storage_context =

[Peter Kasting, 2012/08/07 01:31:54]

Nit: I'd probably just do:

  content::BrowserContext::GetDefaultDOMStorageContext(profile_)->
      StartScavengingUnusedSessionStorage();

(2 places)

[marja, 2012/08/07 07:31:22]

Done.

+          content::BrowserContext::GetDefaultDOMStorageContext(profile_);
+      dom_storage_context->StartScavengingUnusedSessionStorage();
       return FinishedTabCreation(false, false);
     }
 
 #if defined(OS_CHROMEOS)
     chromeos::BootTimesLoader::Get()->AddLoginTimeMarker(
         "SessionRestore-CreatingTabs-Start", false);
 #endif
     StartTabCreation();
 
     // After the for loop this contains the last TABBED_BROWSER. Is null if no
@@ skipping 68 matching lines @@
 #if defined(OS_CHROMEOS)
     chromeos::BootTimesLoader::Get()->AddLoginTimeMarker(
         "SessionRestore-CreatingTabs-End", false);
 #endif
     // If last_browser is NULL and urls_to_open_ is non-empty,
     // FinishedTabCreation will create a new TabbedBrowser and add the urls to
     // it.
     Browser* finished_browser = FinishedTabCreation(true, has_tabbed_browser);
     if (finished_browser)
       last_browser = finished_browser;
+
+    // sessionStorages needed for the session restore have now been recreated
+    // by RestoreTab. Now it's safe for the DOM storage system to start
+    // deleting leftover data.
+    content::DOMStorageContext* dom_storage_context =
+        content::BrowserContext::GetDefaultDOMStorageContext(profile_);
+    dom_storage_context->StartScavengingUnusedSessionStorage();
     return last_browser;
   }
 
   // Record an app launch event (if appropriate) for a tab which is about to
   // be restored. Callers should ensure that selected_index is within the
   // bounds of tab.navigations before calling.
   void RecordAppLaunchForTab(Browser* browser,
                              const SessionTab& tab,
                              int selected_index) {
     DCHECK(selected_index >= 0 &&
@@ skipping 255 matching lines @@
   if (active_session_restorers == NULL)
     return false;
   for (std::set<SessionRestoreImpl*>::const_iterator it =
            active_session_restorers->begin();
        it != active_session_restorers->end(); ++it) {
     if ((*it)->profile() == profile)
       return true;
   }
   return false;
 }