Fix a bug that causes a DCHECK to sometimes get it for no good reason.

content/browser/appcache/appcache_request_handler.cc

Index: content/browser/appcache/appcache_request_handler.cc
diff --git a/content/browser/appcache/appcache_request_handler.cc b/content/browser/appcache/appcache_request_handler.cc
index 5dc11036badff1a13328496f9a0f4828d5b64eaa..4434d1fbded155a049e0eab39754598353bb34c3 100644
--- a/content/browser/appcache/appcache_request_handler.cc
+++ b/content/browser/appcache/appcache_request_handler.cc
@@ -380,7 +380,7 @@ void AppCacheRequestHandler::OnMainResponseFound(
     return;
   }
 
-  if (IsResourceTypeFrame(resource_type_) && cache_id != kAppCacheNoCacheId) {
+  if (IsMainResourceType(resource_type_) && cache_id != kAppCacheNoCacheId) {
     // AppCacheHost loads and holds a reference to the main resource cache
     // for two reasons, firstly to preload the cache into the working set
     // in advance of subresource loads happening, secondly to prevent the