Persist sessionStorage on disk.

content/public/browser/dom_storage_context.h

Index: content/public/browser/dom_storage_context.h
diff --git a/content/public/browser/dom_storage_context.h b/content/public/browser/dom_storage_context.h
index 3fb05952678b80655dee69b50210b83749a16bf2..0e0502ff761b4c5187c7b33e7645df01f5db1ea5 100644
--- a/content/public/browser/dom_storage_context.h
+++ b/content/public/browser/dom_storage_context.h
@@ -18,6 +18,7 @@ class FilePath;
 namespace content {
 
 class BrowserContext;
+class SessionStorageNamespace;
 
 // Represents the per-BrowserContext Local Storage data.
 class DOMStorageContext {
@@ -41,6 +42,14 @@ class DOMStorageContext {
   virtual void DeleteForOrigin(const string16& origin_id) = 0;
   virtual void DeleteLocalStorageFile(const FilePath& file_path) = 0;
 
+  // Called when the sessionStorage for |persistent_namespace_id| can safely be
+  // deleted (it won't be used by session restore).
+  virtual void DoomSessionStorage(
+      const std::string& persistent_namespace_id) = 0;
+
+  virtual scoped_refptr<SessionStorageNamespace> RecreateSessionStorage(
+      const std::string& persistent_id) = 0;
+
  protected:
   virtual ~DOMStorageContext() {}
 };