Extensions: Move id_util functions to crx_file component.

extensions/browser/external_provider_interface.h

Index: extensions/browser/external_provider_interface.h
diff --git a/extensions/browser/external_provider_interface.h b/extensions/browser/external_provider_interface.h
index dd80e319f661767d6f3217d50f1064d745173d38..d14fc7c8ffd2e9f40456fd6b4d85571fe58ea71a 100644
--- a/extensions/browser/external_provider_interface.h
+++ b/extensions/browser/external_provider_interface.h
@@ -27,7 +27,8 @@ class ExternalProviderInterface {
   // caller what extensions are registered, and which |id|, |version| and |path|
   // they have. See also VisitRegisteredExtension below. Ownership of |version|
   // is not transferred to the visitor.  Callers of the methods below must
-  // ensure that |id| is a valid extension id (use Extension::IdIsValid(id)).
+  // ensure that |id| is a valid extension id (use
+  // crx_file::id_util::IdIsValid(id)).
   class VisitorInterface {
    public:
     // Return true if the extension install will proceed.  Install will not