Add link preload as=document support

third_party/WebKit/public/platform/WebURLRequest.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 83 matching lines @@
         RequestContextWorker,
         RequestContextXMLHttpRequest,
         RequestContextXSLT
     };
 
     // Corresponds to Fetch's "context frame type": http://fetch.spec.whatwg.org/#concept-request-context-frame-type
     enum FrameType {
         FrameTypeAuxiliary,
         FrameTypeNested,
         FrameTypeNone,
-        FrameTypeTopLevel
+        FrameTypeTopLevel,
+        FrameTypePreload
     };
 
     enum FetchRequestMode {
         FetchRequestModeSameOrigin,
         FetchRequestModeNoCORS,
         FetchRequestModeCORS,
         FetchRequestModeCORSWithForcedPreflight,
         FetchRequestModeNavigate
     };
 
@@ skipping 159 matching lines @@
     BLINK_PLATFORM_EXPORT void setFetchCredentialsMode(FetchCredentialsMode);
 
     // The redirect mode which is used in Fetch API.
     BLINK_PLATFORM_EXPORT FetchRedirectMode getFetchRedirectMode() const;
     BLINK_PLATFORM_EXPORT void setFetchRedirectMode(FetchRedirectMode);
 
     // The LoFi state which determines whether to request a Lo-Fi version of the resource.
     BLINK_PLATFORM_EXPORT LoFiState getLoFiState() const;
     BLINK_PLATFORM_EXPORT void setLoFiState(LoFiState);
 
+    // Is the request triggered by a link preload?
+    BLINK_PLATFORM_EXPORT bool linkPreload() const;
+
     // Extra data associated with the underlying resource request. Resource
     // requests can be copied. If non-null, each copy of a resource requests
     // holds a pointer to the extra data, and the extra data pointer will be
     // deleted when the last resource request is destroyed. Setting the extra
     // data pointer will cause the underlying resource request to be
     // dissociated from any existing non-null extra data pointer.
     BLINK_PLATFORM_EXPORT ExtraData* getExtraData() const;
     BLINK_PLATFORM_EXPORT void setExtraData(ExtraData*);
 
     BLINK_PLATFORM_EXPORT Priority getPriority() const;
@@ skipping 37 matching lines @@
     // instance it contains.
     std::unique_ptr<ResourceRequestContainer> m_ownedResourceRequest;
 
     // Should never be null.
     ResourceRequest* m_resourceRequest;
 };
 
 } // namespace blink
 
 #endif