Revert of OOPIF: Specify previous sibling frames when creating new RenderFrames.

content/browser/frame_host/frame_tree_node.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_
 #define CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 105 matching lines @@
   const FrameReplicationState& current_replication_state() const {
     return replication_state_;
   }
 
   RenderFrameHostImpl* current_frame_host() const {
     return render_manager_.current_frame_host();
   }
 
   bool IsDescendantOf(FrameTreeNode* other) const;
 
-  // Return the node immediately preceding this node in its parent's
-  // |children_|, or nullptr if there is no such node.
-  FrameTreeNode* PreviousSibling() const;
-
   // Returns true if this node is in a loading state.
   bool IsLoading() const;
 
   // Returns this node's loading progress.
   double loading_progress() const { return loading_progress_; }
 
   NavigationRequest* navigation_request() { return navigation_request_.get(); }
 
   // PlzNavigate
   // Takes ownership of |navigation_request| and makes it the current
@@ skipping 84 matching lines @@
   // Owns an ongoing NavigationRequest until it is ready to commit. It will then
   // be reset and a RenderFrameHost will be responsible for the navigation.
   scoped_ptr<NavigationRequest> navigation_request_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameTreeNode);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_