PlzNavigate: preserve SourceLocation when navigating

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 211 matching lines @@
   }
 
   // CSP layout tests verify that preloads are subject to access checks by
   // seeing if they are in the `preload started` list. Therefore do not add
   // them to the list if the load is immediately denied.
   if (resource && !resource->resourceError().isAccessCheck())
     fetcher()->preloadStarted(resource);
   return resource;
 }
 
+void DocumentLoader::setSourceLocation(
+    std::unique_ptr<SourceLocation> sourceLocation) {
+  m_sourceLocation = std::move(sourceLocation);
+}
+
+std::unique_ptr<SourceLocation> DocumentLoader::copySourceLocation() const {
+  return m_sourceLocation ? m_sourceLocation->clone() : nullptr;
+}
+
 void DocumentLoader::dispatchLinkHeaderPreloads(
     ViewportDescriptionWrapper* viewport,
     LinkLoader::MediaPreloadPolicy mediaPolicy) {
   LinkLoader::loadLinksFromHeader(
       response().httpHeaderField(HTTPNames::Link), response().url(),
       m_frame->document(), NetworkHintsInterfaceImpl(),
       LinkLoader::OnlyLoadResources, mediaPolicy, viewport);
 }
 
 void DocumentLoader::didChangePerformanceTiming() {
@@ skipping 570 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