Allow to clear session and local storage when not backed on disk

content/browser/dom_storage/dom_storage_namespace.h

Index: content/browser/dom_storage/dom_storage_namespace.h
diff --git a/content/browser/dom_storage/dom_storage_namespace.h b/content/browser/dom_storage/dom_storage_namespace.h
index 238b7ca554e75c65c94d646cf6963b71457049af..f06012bc1624f8d45562a3a1d8e95d95382bf415 100644
--- a/content/browser/dom_storage/dom_storage_namespace.h
+++ b/content/browser/dom_storage/dom_storage_namespace.h
@@ -52,6 +52,7 @@ class CONTENT_EXPORT DOMStorageNamespace
   const std::string& persistent_namespace_id() const {
     return persistent_namespace_id_;
   }
+  void ReadOrigins(std::vector<GURL>* origins) const;

[michaeln, 2016/05/05 00:38:23]

Can you rename to GetOriginsWithAreas()?

The more generic method name is a little misleading, "read" often means from
disk and the method sounds like it will return all origins in the namespace
including those without loaded areas. But neither of those are true.

Also please move this method down to the bottom of the public method list (and
move the method body in the .cc file down too)

[Julien Isorce Samsung, 2016/05/05 11:05:04]

Done.

 
   // Returns the storage area for the given origin,
   // creating instance if needed. Each call to open