Give FrameTreeNodes a browser-global ID for use in navigation.

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"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
 namespace content {
 
 class RenderFrameHostImpl;
 
 // When a page contains iframes, its renderer process maintains a tree structure
 // of those frames. We are mirroring this tree in the browser process. This
 // class represents a node in this tree and is a wrapper for all objects that
 // are frame-specific (as opposed to page-specific).
 class CONTENT_EXPORT FrameTreeNode {
  public:
   static const int64 kInvalidFrameId;
 
-  FrameTreeNode(int64 frame_id, const std::string& name,
+  FrameTreeNode(int64 frame_id,
+                const std::string& name,
                 scoped_ptr<RenderFrameHostImpl> render_frame_host);
   ~FrameTreeNode();
 
   void AddChild(scoped_ptr<FrameTreeNode> child);
-  void RemoveChild(int64 child_id);
+  void RemoveChild(FrameTreeNode* child);
 
   // Transitional API allowing the RenderFrameHost of a FrameTreeNode
   // representing the main frame to be provided by someone else. After
   // this is called, the FrameTreeNode no longer owns its RenderFrameHost.
   //
   // This should only be used for the main frame (aka root) in a frame tree.
   //
   // TODO(ajwong): Remove this method once the main frame RenderFrameHostImpl is
   // no longer owned by the RenderViewHostImpl.
   void ResetForMainFrame(RenderFrameHostImpl* new_render_frame_host);
 
+  int64 frame_tree_node_id() const {
+    return frame_tree_node_id_;
+  }
+
+  // DO NOT USE.  Only used by FrameTree until we replace renderer-specific
+  // frame IDs with RenderFrameHost routing IDs.
   void set_frame_id(int64 frame_id) {
     DCHECK_EQ(frame_id_, kInvalidFrameId);
     frame_id_ = frame_id;
   }
-
   int64 frame_id() const {
     return frame_id_;
   }
 
   const std::string& frame_name() const {
     return frame_name_;
   }
 
   size_t child_count() const {
     return children_.size();
   }
 
   FrameTreeNode* child_at(size_t index) const {
     return children_[index];
   }
 
   const GURL& current_url() const {
     return current_url_;
   }
 
   void set_current_url(const GURL& url) {
     current_url_ = url;
   }
 
   RenderFrameHostImpl* render_frame_host() const {
     return render_frame_host_;
   }
 
  private:
-  // The unique identifier for the frame in the page.
+  // The next available browser-global FrameTreeNode ID.
+  static int64 next_frame_tree_node_id_;
+
+  // A browser-global identifier for the frame in the page, which stays stable
+  // even if the frame does a cross-process navigation.
+  const int64 frame_tree_node_id_;
+
+  // The renderer-specific identifier for the frame in the page.
+  // TODO(creis): Remove this in favor of the RenderFrameHost's routing ID once
+  // we create FrameTreeNodes for all frames (even without a flag), since this
+  // value can change after cross-process navigations.
   int64 frame_id_;
 
   // The assigned name of the frame. This name can be empty, unlike the unique
   // name generated internally in the DOM tree.
   std::string frame_name_;
 
   // The immediate children of this specific frame.
   ScopedVector<FrameTreeNode> children_;
 
   // When ResetForMainFrame() is called, this is set to false and the
@@ skipping 17 matching lines @@
   // TODO(creis): Remove this when we can store subframe URLs in the
   // NavigationController.
   GURL current_url_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameTreeNode);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_