Revert of Drop CreateChildFrame messages when swapping out.

content/browser/frame_host/frame_tree.cc

Index: content/browser/frame_host/frame_tree.cc
diff --git a/content/browser/frame_host/frame_tree.cc b/content/browser/frame_host/frame_tree.cc
index ec67d8d5a624993f4c55b0436fe3abc87aaebd6c..3415e46780ea6f1145fe1968a2f107a6f842be5c 100644
--- a/content/browser/frame_host/frame_tree.cc
+++ b/content/browser/frame_host/frame_tree.cc
@@ -143,16 +143,8 @@
 }
 
 RenderFrameHostImpl* FrameTree::AddFrame(FrameTreeNode* parent,
-                                         int process_id,
                                          int new_routing_id,
                                          const std::string& frame_name) {
-  // A child frame always starts with an initial empty document, which means
-  // it is in the same SiteInstance as the parent frame. Ensure that the process
-  // which requested a child frame to be added is the same as the process of the
-  // parent node.
-  if (parent->current_frame_host()->GetProcess()->GetID() != process_id)
-    return nullptr;
-
   scoped_ptr<FrameTreeNode> node(new FrameTreeNode(
       this, parent->navigator(), render_frame_delegate_, render_view_delegate_,
       render_widget_delegate_, manager_delegate_, frame_name));
@@ -162,7 +154,7 @@
   CHECK(result.second);
   FrameTreeNode* node_ptr = node.get();
   // AddChild is what creates the RenderFrameHost.
-  parent->AddChild(node.Pass(), process_id, new_routing_id);
+  parent->AddChild(node.Pass(), new_routing_id);
   return node_ptr->current_frame_host();
 }