Deleting cookies by setting the expires attribute on them with an empty value...

net/base/cookie_store.h

Index: net/base/cookie_store.h
===================================================================
--- net/base/cookie_store.h	(revision 35707)
+++ net/base/cookie_store.h	(working copy)
@@ -59,6 +59,10 @@
     return NULL;
   };
 
+  // Deletes the passed in cookie for the specified URL.
+  virtual void DeleteCookie(const GURL& url,
+                            const std::string& cookie_name) = 0;
+
  protected:
   friend class base::RefCountedThreadSafe<CookieStore>;
   virtual ~CookieStore() {}