Remove opener URLs from CreateNewWindowParams.

Now that this message is serviced on the UI thread, we can use the
real values there, which are more trustworthy anyway. This fixes
bug 674307.

BUG=466297,674307
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2837683002
Cr-Commit-Position: refs/heads/master@{#466796}
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index d9457e9..661b4db 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -2099,8 +2099,8 @@
       !delegate_->ShouldCreateWebContents(
           this, source_site_instance, render_view_route_id, main_frame_route_id,
           main_frame_widget_route_id, params.window_container_type,
-          params.opener_url, params.frame_name, params.target_url, partition_id,
-          session_storage_namespace)) {
+          opener->GetLastCommittedURL(), params.frame_name, params.target_url,
+          partition_id, session_storage_namespace)) {
     // Note: even though we're not creating a WebContents here, it could have
     // been created by the embedder so ensure that the RenderFrameHost is
     // properly initialized.