OOPIF: Fix subframe back/forward after recreating FTNs (try #2).

content/browser/frame_host/frame_navigation_entry.h

 // Copyright 2015 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_NAVIGATION_ENTRY_H_
 #define CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "content/browser/site_instance_impl.h"
 #include "content/public/common/page_state.h"
 #include "content/public/common/referrer.h"
 
 namespace content {
 
-// Represents a session history item for a particular frame.
+// Represents a session history item for a particular frame.  It is matched with
+// corresponding FrameTreeNodes using unique name (or by the root position).
 //
 // This class is refcounted and can be shared across multiple NavigationEntries.
 // For now, it is owned by a single NavigationEntry and only tracks the main
 // frame.
 //
 // If SiteIsolationPolicy::UseSubframeNavigationEntries is true, there will be a
 // tree of FrameNavigationEntries in each NavigationEntry, one per frame.
 // TODO(creis): Share these FrameNavigationEntries across NavigationEntries if
 // the frame hasn't changed.
 class CONTENT_EXPORT FrameNavigationEntry
     : public base::RefCounted<FrameNavigationEntry> {
  public:
-  explicit FrameNavigationEntry(int frame_tree_node_id);
-  FrameNavigationEntry(int frame_tree_node_id,
-                       const std::string& frame_unique_name,
+  FrameNavigationEntry();
+  FrameNavigationEntry(const std::string& frame_unique_name,
                        int64_t item_sequence_number,
                        int64_t document_sequence_number,
                        scoped_refptr<SiteInstanceImpl> site_instance,
                        const GURL& url,
                        const Referrer& referrer,
                        const std::string& method,
                        int64_t post_id);
 
   // Creates a copy of this FrameNavigationEntry that can be modified
   // independently from the original.
   FrameNavigationEntry* Clone() const;
 
   // Updates all the members of this entry.
   void UpdateEntry(const std::string& frame_unique_name,
                    int64_t item_sequence_number,
                    int64_t document_sequence_number,
                    SiteInstanceImpl* site_instance,
                    const GURL& url,
                    const Referrer& referrer,
                    const PageState& page_state,
                    const std::string& method,
                    int64_t post_id);
 
-  // The ID of the FrameTreeNode this entry is for.  -1 for the main frame,
-  // since we don't always know the FrameTreeNode ID when creating the overall
-  // NavigationEntry.
-  // TODO(creis): Consider removing |frame_tree_node_id| in favor of
-  // |frame_unique_name|, if we can move unique name computation to the browser
-  // process.
-  int frame_tree_node_id() const { return frame_tree_node_id_; }
-  void set_frame_tree_node_id(int frame_tree_node_id) {
-    frame_tree_node_id_ = frame_tree_node_id;
-  }
-
   // The unique name of the frame this entry is for.  This is a stable name for
   // the frame based on its position in the tree and relation to other named
   // frames, which does not change after cross-process navigations or restores.
   // Only the main frame can have an empty name.
   //
   // This is unique relative to other frames in the same page, but not among
   // other pages (i.e., not globally unique).
   const std::string& frame_unique_name() const { return frame_unique_name_; }
   void set_frame_unique_name(const std::string& frame_unique_name) {
     frame_unique_name_ = frame_unique_name;
@@ skipping 44 matching lines @@
   friend class base::RefCounted<FrameNavigationEntry>;
   virtual ~FrameNavigationEntry();
 
   // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
   // Add all new fields to |UpdateEntry|.
   // TODO(creis): These fields have implications for session restore.  This is
   // currently managed by NavigationEntry, but the logic will move here.
   // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
 
   // See the accessors above for descriptions.
-  int frame_tree_node_id_;
   std::string frame_unique_name_;
   int64_t item_sequence_number_;
   int64_t document_sequence_number_;
   scoped_refptr<SiteInstanceImpl> site_instance_;
   GURL url_;
   Referrer referrer_;
   // TODO(creis): Change this to FrameState.
   PageState page_state_;
   std::string method_;
   int64_t post_id_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameNavigationEntry);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_