content: Change appcache_interfaces.* to use contants from url/ component.

content/common/appcache_interfaces.h

Index: content/common/appcache_interfaces.h
diff --git a/content/common/appcache_interfaces.h b/content/common/appcache_interfaces.h
index ba5847e5c1eea2195f135b3bebdd70c709bd3ddc..08a9ea2b47f105ae3decbff18d225ee64d0e1a0d 100644
--- a/content/common/appcache_interfaces.h
+++ b/content/common/appcache_interfaces.h
@@ -163,11 +163,6 @@ class CONTENT_EXPORT AppCacheBackend {
 };
 
 // Useful string constants.
-// Note: These are also defined elsewhere in the chrome code base in
-// url_contants.h .cc, however the content library can not have
-// any dependencies on the chrome library, so we can't use them in here.
-CONTENT_EXPORT extern const char kHttpScheme[];
-CONTENT_EXPORT extern const char kHttpsScheme[];
 CONTENT_EXPORT extern const char kHttpGETMethod[];
 CONTENT_EXPORT extern const char kHttpHEADMethod[];