Create and store persistent unique ids for sessionStorage.

content/public/browser/session_storage_namespace.h

Index: content/public/browser/session_storage_namespace.h
diff --git a/content/public/browser/session_storage_namespace.h b/content/public/browser/session_storage_namespace.h
index 5b17d0ceaebd56e8c45794931e5525c6d17d47f8..2469ad5d4a4a7c833a642776b0fe1bdec200f331 100644
--- a/content/public/browser/session_storage_namespace.h
+++ b/content/public/browser/session_storage_namespace.h
@@ -6,19 +6,33 @@
 #define CONTENT_PUBLIC_BROWSER_SESSION_STORAGE_NAMESPACE_H_
 #pragma once
 
+#include <string>
+
+#include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 
 namespace content {
 
 // This is a ref-counted class that represents a SessionStorageNamespace.
 // On destruction it ensures that the storage namespace is destroyed.
-// NOTE: That if we're shutting down, we don't strictly need to do this, but
-//       it keeps valgrind happy.
 class SessionStorageNamespace
     : public base::RefCountedThreadSafe<SessionStorageNamespace> {
+ public:
+  SessionStorageNamespace() {}
+
+  // Returns the ID of the |SessionStorageNamespace|. The ID is unique among all
+  // SessionStorageNamespace objects, but not unique across browser runs.
+  virtual int64 id() const = 0;
+
+  // Returns the persistent ID for the |SessionStorageNamespace|. The ID is
+  // unique across browser runs.
+  virtual const std::string& persistent_id() const = 0;
+
  protected:
   friend class base::RefCountedThreadSafe<SessionStorageNamespace>;
   virtual ~SessionStorageNamespace() {}
+
+  DISALLOW_COPY_AND_ASSIGN(SessionStorageNamespace);
 };
 
 }  // namespace content