Add suborigin logic to url::Origin

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 a4aba1e91e1b4f384a0e0eaa9891b8d6e062965c..c69723e61c453e3a72eac630eefc08df12af9fb8 100644
--- a/content/public/browser/dom_storage_context.h
+++ b/content/public/browser/dom_storage_context.h
@@ -40,6 +40,17 @@ class DOMStorageContext {
       const GetSessionStorageUsageCallback& callback) = 0;
 
   // Deletes the local storage data for the given origin.
+  //
+  // |origin| must not be a suborigin. For the given origin, it will delete
+  // all localStorage associated with suborigins at the physical origin of
+  // |origin|. (that is, deletion of http://example.com will also delete
+  // http-so://foo.example.com). See
+  // https://w3c.github.io/webappsec-suborigins/.
+  virtual void DeleteLocalStorageForPhysicalOrigin(const GURL& origin) = 0;
+
+  // Same as above, but extracts the physical origin from |origin| to do the
+  // deletion, so it is unnecessary to guarantee that |origin| doesn't have a
+  // suborigin.
   virtual void DeleteLocalStorage(const GURL& origin) = 0;

[michaeln, 2016/10/21 23:07:12]

Looking at this again i think we should retain the ability to delete a singular
area, and add a seperate function to delete the multiple areas related to a
physorigin. The latter function builds on the former function. There are very
few callsites, so updating to use DeleteLocalStorageForPhysicalOrigin() where
appropiate is easy enough.

DeleteLocalStorage() deletes just one specific <schm,host,port> identified
DOMStorageArea (the function you're CL is currently calling
DeleteAndClearStorageNamespaceForOrigin) 

and 

DeleteLocalStorageForPhysicalOrigin() deletes all areas (top level and sub
origins) for the ori.PhysOrigin of the origin provided.

[jww, 2016/10/22 00:43:12]

Done.

 
   // Deletes the session storage data identified by |usage_info|.