OOPIF: Remove the FrameTreeNode when a RemoteFrame is detached.

content/renderer/render_frame_proxy.cc

Index: content/renderer/render_frame_proxy.cc
diff --git a/content/renderer/render_frame_proxy.cc b/content/renderer/render_frame_proxy.cc
index ae6d699ae739783c76a70f4dcb05fcd246c45949..1523fb7356ad8116068df6344f65f923313efb1b 100644
--- a/content/renderer/render_frame_proxy.cc
+++ b/content/renderer/render_frame_proxy.cc
@@ -304,9 +304,14 @@ void RenderFrameProxy::OnDidUpdateName(const std::string& name) {
 }
 
 void RenderFrameProxy::frameDetached() {
-  if (web_frame_->parent())
+  if (web_frame_->parent()) {
     web_frame_->parent()->removeChild(web_frame_);
 
+    // Let the browser process know this subframe is removed, so that it is
+    // destroyed in its current process.
+    Send(new FrameHostMsg_Detach(routing_id_));
+  }
+
   web_frame_->close();
   delete this;
 }