PlzNavigate: preserve SourceLocation when navigating

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

Index: third_party/WebKit/Source/core/loader/DocumentLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/DocumentLoader.cpp b/third_party/WebKit/Source/core/loader/DocumentLoader.cpp
index 8c7197c9cf02e49345d3896bd0f73b46319f9d07..a5c3b32a58dcd5f2e22efc14529298a64ef303ba 100644
--- a/third_party/WebKit/Source/core/loader/DocumentLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/DocumentLoader.cpp
@@ -229,6 +229,15 @@ Resource* DocumentLoader::startPreload(Resource::Type type,
   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) {