Persist sessionStorage on disk.

webkit/dom_storage/dom_storage_area.h

Index: webkit/dom_storage/dom_storage_area.h
diff --git a/webkit/dom_storage/dom_storage_area.h b/webkit/dom_storage/dom_storage_area.h
index d0b09a77a57b6b246cbbd6f9aab2e5dffc9eb2bf..38ff1e94e6b161dff63eaa162b81b7c1ddee7f73 100644
--- a/webkit/dom_storage/dom_storage_area.h
+++ b/webkit/dom_storage/dom_storage_area.h
@@ -12,6 +12,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/nullable_string16.h"
 #include "base/string16.h"
+#include "base/synchronization/lock.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/dom_storage/dom_storage_types.h"
 
@@ -20,6 +21,7 @@ namespace dom_storage {
 class DomStorageDatabaseAdapter;
 class DomStorageMap;
 class DomStorageTaskRunner;
+class SessionStorageDatabase;
 
 // Container for a per-origin Map of key/value pairs potentially
 // backed by storage on disk and lazily commits changes to disk.
@@ -37,10 +39,11 @@ class DomStorageArea
                  const FilePath& directory,
                  DomStorageTaskRunner* task_runner);
 
-  // Session storage.
+  // Session storage. Backed on disk if |session_storage_backing| is not NULL.
   DomStorageArea(int64 namespace_id,
                  const std::string& persistent_namespace_id,
                  const GURL& origin,
+                 SessionStorageDatabase* session_storage_backing,
                  DomStorageTaskRunner* task_runner);
 
   const GURL& origin() const { return origin_; }
@@ -111,6 +114,8 @@ class DomStorageArea
   void CommitChanges(const CommitBatch* commit_batch);
   void OnCommitComplete();
 
+  void DeleteOriginInCommitSequence();
+
   void ShutdownInCommitSequence();
 
   int64 namespace_id_;
@@ -120,10 +125,16 @@ class DomStorageArea
   scoped_refptr<DomStorageTaskRunner> task_runner_;
   scoped_refptr<DomStorageMap> map_;
   scoped_ptr<DomStorageDatabaseAdapter> backing_;
+  scoped_refptr<SessionStorageDatabase> session_storage_backing_;
   bool is_initial_import_done_;
   bool is_shutdown_;
   scoped_ptr<CommitBatch> commit_batch_;
   int commit_batches_in_flight_;
+
+  // |deletion_in_progress_| is true if the data is getting deleted because of a
+  // |DeleteOrigin call. |deletion_in_progress_lock_| guards it.
+  bool deletion_in_progress_;
+  base::Lock deletion_in_progress_lock_;
 };
 
 }  // namespace dom_storage