Almost finish moving context_menu_node_ from RenderViewImpl to RenderFrameImpl.

content/browser/frame_host/frame_tree.cc

Index: content/browser/frame_host/frame_tree.cc
===================================================================
--- content/browser/frame_host/frame_tree.cc	(revision 255719)
+++ content/browser/frame_host/frame_tree.cc	(working copy)
@@ -71,7 +71,8 @@
                               render_view_delegate,
                               render_widget_delegate,
                               manager_delegate,
-                              std::string())) {
+                              std::string())),
+      focused_frame_tree_node_id_(-1) {
 }
 
 FrameTree::~FrameTree() {
@@ -138,6 +139,7 @@
 
 void FrameTree::ResetForMainFrameSwap() {
   root_->ResetForNewProcess();
+  focused_frame_tree_node_id_ = -1;
 }
 
 void FrameTree::RenderProcessGone(RenderViewHost* render_view_host) {
@@ -154,6 +156,14 @@
   return root_->current_frame_host();
 }
 
+FrameTreeNode* FrameTree::GetFocusedFrame() {
+  return FindByID(focused_frame_tree_node_id_);
+}
+
+void FrameTree::SetFocusedFrame(FrameTreeNode* node) {
+  focused_frame_tree_node_id_ = node->frame_tree_node_id();
+}
+
 void FrameTree::SetFrameRemoveListener(
     const base::Callback<void(RenderViewHostImpl*, int)>& on_frame_removed) {
   on_frame_removed_ = on_frame_removed;