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

third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp

Index: third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
diff --git a/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp b/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
index 576acc203db093a1574fcc8974064251e48cfc19..417aab0fb0fad6e7e5297c5dd16891691923aa69 100644
--- a/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
+++ b/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
@@ -681,11 +681,11 @@ DocumentLoader* FrameLoaderClientImpl::createDocumentLoader(
     LocalFrame* frame,
     const ResourceRequest& request,
     const SubstituteData& data,
-    ClientRedirectPolicy clientRedirectPolicy) {
-  WebDataSourceImpl* ds =
-      WebDataSourceImpl::create(frame, request, data, clientRedirectPolicy);
-  if (m_webFrame->client())
-    m_webFrame->client()->didCreateDataSource(m_webFrame, ds);
+    ClientRedirectPolicy clientRedirectPolicy,
+    Document* requestorDocument) {
+  WebDataSourceImpl* ds = WebDataSourceImpl::create(
+      frame, request, data, clientRedirectPolicy, requestorDocument);
+  m_webFrame->client()->didCreateDataSource(m_webFrame, ds);
   return ds;
 }