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

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

Index: third_party/WebKit/Source/core/loader/FrameLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameLoader.cpp b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
index bcea454f7557c90093ad816a74a70254c2bb3fc1..28b0e683f96ebd4116169ca4879251dc67dbbb5f 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -221,9 +221,9 @@ void FrameLoader::init() {
   initialRequest.setFrameType(m_frame->isMainFrame()
                                   ? WebURLRequest::FrameTypeTopLevel
                                   : WebURLRequest::FrameTypeNested);
-  m_provisionalDocumentLoader =
-      client()->createDocumentLoader(m_frame, initialRequest, SubstituteData(),
-                                     ClientRedirectPolicy::NotClientRedirect);
+  m_provisionalDocumentLoader = client()->createDocumentLoader(
+      m_frame, initialRequest, SubstituteData(),
+      ClientRedirectPolicy::NotClientRedirect, nullptr);
   m_provisionalDocumentLoader->startLoadingMainResource();
   m_frame->document()->cancelParsing();
   m_stateMachine.advanceTo(
@@ -1685,7 +1685,7 @@ void FrameLoader::startLoad(FrameLoadRequest& frameLoadRequest,
       m_frame, request, frameLoadRequest.substituteData().isValid()
                             ? frameLoadRequest.substituteData()
                             : defaultSubstituteDataForURL(request.url()),
-      frameLoadRequest.clientRedirect());
+      frameLoadRequest.clientRedirect(), frameLoadRequest.requestorDocument());
   m_provisionalDocumentLoader->setNavigationType(navigationType);
   m_provisionalDocumentLoader->setReplacesCurrentHistoryItem(
       type == FrameLoadTypeReplaceCurrentItem);