Expose the initiating origin/URL of a navigation in the Blink public API

third_party/WebKit/Source/core/loader/DocumentLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 79 matching lines @@
   // browsing context was created.
   //
   // Note: We generalize this to all "blank" URLs and invalid URLs because we
   // treat all of these URLs as about:blank.
   return url.isEmpty() || url.protocolIsAbout();
 }
 
 DocumentLoader::DocumentLoader(LocalFrame* frame,
                                const ResourceRequest& req,
                                const SubstituteData& substituteData,
-                               ClientRedirectPolicy clientRedirectPolicy)
+                               ClientRedirectPolicy clientRedirectPolicy,
+                               Document* requestorDocument)
     : m_frame(frame),
       m_fetcher(FrameFetchContext::createContextAndFetcher(this, nullptr)),
+      m_requestorDocument(requestorDocument),
       m_originalRequest(req),
       m_substituteData(substituteData),
       m_request(req),
       m_isClientRedirect(clientRedirectPolicy ==
                          ClientRedirectPolicy::ClientRedirect),
       m_replacesCurrentHistoryItem(false),
       m_dataReceived(false),
       m_navigationType(NavigationTypeOther),
       m_documentLoadTiming(*this),
       m_timeOfLastDataReceived(0.0),
@@ skipping 18 matching lines @@
   DCHECK(!m_frame);
   DCHECK(!m_mainResource);
   DCHECK(!m_applicationCacheHost);
 }
 
 DEFINE_TRACE(DocumentLoader) {
   visitor->trace(m_frame);
   visitor->trace(m_fetcher);
   visitor->trace(m_mainResource);
   visitor->trace(m_writer);
+  visitor->trace(m_requestorDocument);
   visitor->trace(m_documentLoadTiming);
   visitor->trace(m_applicationCacheHost);
   visitor->trace(m_contentSecurityPolicy);
   RawResourceClient::trace(visitor);
 }
 
 unsigned long DocumentLoader::mainResourceIdentifier() const {
   return m_mainResource ? m_mainResource->identifier() : 0;
 }
 
@@ skipping 484 matching lines @@
   WeakIdentifierMap<DocumentLoader>::notifyObjectDestroyed(this);
   clearMainResourceHandle();
   m_frame = nullptr;
 }
 
 void DocumentLoader::clearMainResourceHandle() {
   if (!m_mainResource)
     return;
   m_mainResource->removeClient(this);
   m_mainResource = nullptr;
+
+  // TODO(dcheng): This doesn't really belong here.

[dcheng, 2016/11/23 08:32:59]

I'm not sure what the best place to put this is; it's a bit out of place here,
but it also seems to be the best current location for "clean up resources"...

+  m_requestorDocument = nullptr;
 }
 
 bool DocumentLoader::maybeCreateArchive() {
   // Give the archive machinery a crack at this document. If the MIME type is
   // not an archive type, it will return 0.
   if (!isArchiveMIMEType(m_response.mimeType()))
     return false;
 
   DCHECK(m_mainResource);
   ArchiveResource* mainResource =
@@ skipping 138 matching lines @@
                              m_writer ? m_writer->encoding() : emptyAtom, true,
                              ForceSynchronousParsing);
   if (!source.isNull())
     m_writer->appendReplacingData(source);
   endWriting();
 }
 
 DEFINE_WEAK_IDENTIFIER_MAP(DocumentLoader);
 
 }  // namespace blink