Remove WebContentsObserver::ProvisionalChangeToMainFrameUrl and all the code supporting it.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 633774376fc362df32e084afdbbfda586ee446b3..51296ee7e709139f5dfb35d3322b016b11c92aa7 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -2038,24 +2038,6 @@ void RenderFrameImpl::didReceiveServerRedirectForProvisionalLoad(
     blink::WebLocalFrame* frame) {
   DCHECK(!frame_ || frame_ == frame);
   render_view_->history_controller()->RemoveChildrenForRedirect(this);
-  if (frame->parent())
-    return;
-  // Received a redirect on the main frame.
-  WebDataSource* data_source = frame->provisionalDataSource();
-  if (!data_source) {
-    // Should only be invoked when we have a data source.
-    NOTREACHED();
-    return;
-  }
-  std::vector<GURL> redirects;
-  GetRedirectChain(data_source, &redirects);
-  if (redirects.size() >= 2) {
-    Send(new FrameHostMsg_DidRedirectProvisionalLoad(
-        routing_id_,
-        render_view_->page_id_,
-        redirects[redirects.size() - 2],
-        redirects.back()));
-  }
 }
 
 void RenderFrameImpl::didFailProvisionalLoad(blink::WebLocalFrame* frame,