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

Source/web/WebLocalFrameImpl.cpp

Index: Source/web/WebLocalFrameImpl.cpp
diff --git a/Source/web/WebLocalFrameImpl.cpp b/Source/web/WebLocalFrameImpl.cpp
index 0c9744fe66ec5ae744fa64b5993b62a5dcfe32f1..44edfeac29c8b26095604cb90b93dc4eb228201b 100644
--- a/Source/web/WebLocalFrameImpl.cpp
+++ b/Source/web/WebLocalFrameImpl.cpp
@@ -116,6 +116,7 @@
 #include "core/loader/FrameLoadRequest.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/HistoryItem.h"
+#include "core/loader/ManifestLoader.h"
 #include "core/loader/SubstituteData.h"
 #include "core/page/Chrome.h"
 #include "core/page/EventHandler.h"
@@ -151,6 +152,7 @@
 #include "public/platform/WebFloatPoint.h"
 #include "public/platform/WebFloatRect.h"
 #include "public/platform/WebLayer.h"
+#include "public/platform/WebManifestRequest.h"
 #include "public/platform/WebPoint.h"
 #include "public/platform/WebRect.h"
 #include "public/platform/WebSize.h"
@@ -1567,6 +1569,16 @@ WebString WebLocalFrameImpl::layerTreeAsText(bool showDebugInfo) const
     return WebString(frame()->layerTreeAsText(showDebugInfo ? LayerTreeIncludesDebugInfo : LayerTreeNormal));
 }
 
+void WebLocalFrameImpl::requestManifest(WebManifestRequest& request) const
+{
+    if (!frame()) {
+        request.requestFailed(blink::WebManifestRequest::NoLinkManifest);
+        return;
+    }
+
+    ManifestLoader::loadManifest(&request, frame()->document());
+}
+
 // WebLocalFrameImpl public ---------------------------------------------------------
 
 WebLocalFrame* WebLocalFrame::create(WebFrameClient* client)