[NotLanded] Implement the fetching algorithm of the Web Manifest.

Source/core/loader/EmptyClients.h

Index: Source/core/loader/EmptyClients.h
diff --git a/Source/core/loader/EmptyClients.h b/Source/core/loader/EmptyClients.h
index 8b8d49b641eec35fa694616d56395f027e1bdf5c..16ff1d52f7cf1d0467775f296ad40d534e90fef0 100644
--- a/Source/core/loader/EmptyClients.h
+++ b/Source/core/loader/EmptyClients.h
@@ -163,7 +163,7 @@ public:
     virtual String acceptLanguages() OVERRIDE;
 };
 
-class EmptyFrameLoaderClient FINAL : public FrameLoaderClient {
+class EmptyFrameLoaderClient : public FrameLoaderClient {
     WTF_MAKE_NONCOPYABLE(EmptyFrameLoaderClient); WTF_MAKE_FAST_ALLOCATED;
 public:
     EmptyFrameLoaderClient() { }