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

Source/core/loader/FrameLoaderClient.h

Index: Source/core/loader/FrameLoaderClient.h
diff --git a/Source/core/loader/FrameLoaderClient.h b/Source/core/loader/FrameLoaderClient.h
index a8a1fef7c734a14be7bbf36f5a1027561ee3ee9a..8c6dea5567006fef6ca4bfc0064e91835fc04ced 100644
--- a/Source/core/loader/FrameLoaderClient.h
+++ b/Source/core/loader/FrameLoaderClient.h
@@ -36,18 +36,20 @@
 #include "core/loader/NavigationPolicy.h"
 #include "platform/network/ResourceLoadPriority.h"
 #include "platform/weborigin/Referrer.h"
+#include "public/platform/WebManifestError.h"
 #include "wtf/Forward.h"
 #include "wtf/Vector.h"
 #include <v8.h>
 
 namespace blink {
+class WebApplicationCacheHost;
+class WebApplicationCacheHostClient;
 class WebCookieJar;
 class WebRTCPeerConnectionHandler;
 class WebServiceWorkerProvider;
 class WebServiceWorkerProviderClient;
 class WebSocketHandle;
-class WebApplicationCacheHost;
-class WebApplicationCacheHostClient;
+struct WebManifest;
 }
 
 namespace blink {
@@ -228,6 +230,8 @@ namespace blink {
         virtual void didStopAllLoaders() { }
 
         virtual void dispatchDidChangeManifest() { }
+        virtual void dispatchDidLoadManifest(const blink::WebManifest&) { }
+        virtual void dispatchDidFailLoadManifest(blink::WebManifestError) { }
 
         virtual bool isFrameLoaderClientImpl() const { return false; }
     };