Add support for fallback content for the frame. This includes main and subframes.

content/browser/appcache/appcache_request_handler.h

Index: content/browser/appcache/appcache_request_handler.h
diff --git a/content/browser/appcache/appcache_request_handler.h b/content/browser/appcache/appcache_request_handler.h
index 24ee0fcc7456cbd50af6d75a4c43e522325a6630..4e9cbb2226dd73bc8b7487ba7132d7d5ebca5d86 100644
--- a/content/browser/appcache/appcache_request_handler.h
+++ b/content/browser/appcache/appcache_request_handler.h
@@ -166,6 +166,12 @@ class CONTENT_EXPORT AppCacheRequestHandler
                          LoaderCallback callback) override;
   mojom::URLLoaderFactoryPtr MaybeCreateSubresourceFactory() override;
 
+  // Returns true if a fallback response was returned for the network
+  // |response| passed in.
+  bool MaybeGetFallbackForResponse(const ResourceResponseHead& response,
+                                   mojom::URLLoaderClientPtr client,
+                                   mojom::URLLoaderRequest request);
+
   // Data members -----------------------------------------------
 
   // What host we're servicing a request for.
@@ -228,13 +234,6 @@ class CONTENT_EXPORT AppCacheRequestHandler
 
   // Network service related members.
 
-  // In the network service world we are queried via the URLLoaderRequestHandler
-  // interface to see if the navigation request can be handled via the
-  // AppCache. We hold onto the AppCache job created here until the client
-  // binds to it (Serviced via AppCache). If the request cannot be handled via
-  // the AppCache, we delete the job.
-  std::unique_ptr<AppCacheJob> navigation_request_job_;
-
   // In the network service world, points to the getter for the network URL
   // loader.
   scoped_refptr<URLLoaderFactoryGetter> network_url_loader_factory_getter_;