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

public/web/WebLocalFrame.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebLocalFrame_h
 #define WebLocalFrame_h
 
 #include "WebFrame.h"
 
 namespace blink {
@@ skipping 19 matching lines @@
 
     // Returns the frame inside a given frame or iframe element. Returns 0 if
     // the given element is not a frame, iframe or if the frame is empty.
     BLINK_EXPORT static WebLocalFrame* fromFrameOwnerElement(const WebElement&);
 
     // Navigation Transitions  ---------------------------------------------
     virtual void addStyleSheetByURL(const WebString& url) = 0;
     virtual void navigateToSandboxedMarkup(const WebData& markup) = 0;
 
     virtual void sendPings(const WebNode& linkNode, const WebURL& destinationURL) = 0;
+
+    // Manifest ------------------------------------------------------------
+
+    // Called to fetch and parse a frame's manifest. The associated
+    // WebFrameClient will be notified upon completion via
+    // WebFrameClient::didLoadManifest or WebFrameClient::didFailLoadManifest
+    // depending on the call being successful or not.
+    virtual void requestManifest() = 0;
 };
 
 } // namespace blink
 
 #endif // WebLocalFrame_h