Expose RenderFrameHost::GetLastCommittedOrigin().

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 4a016945ec23b1bf395fbb8ff3b46823ca0ce1a9..ec98d5e4681caf22f56ed61256a51ec939cca921 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -313,6 +313,15 @@ GURL RenderFrameHostImpl::GetLastCommittedURL() {
   return frame_tree_node_->current_url();
 }
 
+url::Origin RenderFrameHostImpl::GetLastCommittedOrigin() {
+  // Origin is stored per-FTN, so it's incorrect to call for a non-current RFH.
+  if (this != frame_tree_node_->current_frame_host()) {
+    NOTREACHED() << "Origin information is tracked only for the current host.";
+    return url::Origin();

[Charlie Reis, 2015/11/24 21:00:42]

Sanity check: Since there aren't callers yet, do we want to go further and
enforce this with a CHECK?  Returning an empty Origin as a fallback seems kind
of safe (certainly better than returning some other frame's origin), but I'm not
sure what implications it will have in practice.

[ncarter (slow), 2015/11/24 22:07:33]

Switched to a CHECK based on our face-to-face discussion. This is the sort of
case that makes me wish we had an UMA-logged NOTREACHED().

+  }
+  return frame_tree_node_->current_origin();
+}
+
 gfx::NativeView RenderFrameHostImpl::GetNativeView() {
   RenderWidgetHostView* view = render_view_host_->GetWidget()->GetView();
   if (!view)