Fix a memory leak in a unit test.

net/base/cookie_monster_store_test.h

Index: net/base/cookie_monster_store_test.h
===================================================================
--- net/base/cookie_monster_store_test.h	(revision 100188)
+++ net/base/cookie_monster_store_test.h	(working copy)
@@ -109,6 +109,12 @@
   DISALLOW_COPY_AND_ASSIGN(MockCookieMonsterDelegate);
 };
 
+// Helper to build a single CanonicalCookie.
+CookieMonster::CanonicalCookie BuildCanonicalCookie(
+    const std::string& key,
+    const std::string& cookie_line,
+    const base::Time& creation_time);
+
 // Helper to build a list of CanonicalCookie*s.
 void AddCookieToList(
     const std::string& key,