OOPIF: Fix subframe back/forward after recreating FTNs.

content/browser/frame_host/navigation_entry_impl.h

Index: content/browser/frame_host/navigation_entry_impl.h
diff --git a/content/browser/frame_host/navigation_entry_impl.h b/content/browser/frame_host/navigation_entry_impl.h
index d54d1def9f25e63ca2a5c390c5a04ed1572f1047..cae8754896b2e5efbc6b846a04defb0e95cf6d26 100644
--- a/content/browser/frame_host/navigation_entry_impl.h
+++ b/content/browser/frame_host/navigation_entry_impl.h
@@ -37,8 +37,11 @@ class CONTENT_EXPORT NavigationEntryImpl
     TreeNode(FrameNavigationEntry* frame_entry);
     ~TreeNode();
 
-    // Returns whether this TreeNode corresponds to |frame_tree_node|.
-    bool MatchesFrame(FrameTreeNode* frame_tree_node) const;
+    // Returns whether this TreeNode corresponds to |frame_tree_node|, based on
+    // the FrameTreeNode ID or unique name.  If the unique name matches and
+    // FrameTreeNode ID does not, then this will update the entry's
+    // FrameTreeNode ID (which may be stale if the node was recreated).
+    bool MatchesFrame(FrameTreeNode* frame_tree_node);

[alexmos, 2016/04/06 17:14:22]

This now has the side effect of sometimes updating FTN ID, but the function name
doesn't reflect that, so you don't realize this looking at the call sites.  I
couldn't come up with anything better to suggest though, so I think this is
fine. :)

[Charlie Reis, 2016/04/12 16:25:51]

Yeah, it's a bit awkward for the name to reflect that.  I view it as hopefully
temporary, since we should be able to remove FTN ID entirely from here and just
use unique name (maybe once the browser process generates unique name).  That's
what HistoryController does in the old path.

 
     // Recursively makes a deep copy of TreeNode with copies of each of the
     // FrameNavigationEntries in the subtree.  Replaces the TreeNode
@@ -49,7 +52,7 @@ class CONTENT_EXPORT NavigationEntryImpl
     // NavigationEntries of the same tab.
     scoped_ptr<TreeNode> CloneAndReplace(
         FrameTreeNode* frame_tree_node,
-        FrameNavigationEntry* frame_navigation_entry) const;
+        FrameNavigationEntry* frame_navigation_entry);
 
     // Ref counted pointer that keeps the FrameNavigationEntry alive as long as
     // it is needed by this node's NavigationEntry.
@@ -188,7 +191,6 @@ class CONTENT_EXPORT NavigationEntryImpl
   // Does nothing if there is no entry already and |url| is about:blank, since
   // that does not count as a real commit.
   void AddOrUpdateFrameEntry(FrameTreeNode* frame_tree_node,
-                             const std::string& frame_unique_name,
                              int64_t item_sequence_number,
                              int64_t document_sequence_number,
                              SiteInstanceImpl* site_instance,
@@ -197,17 +199,10 @@ class CONTENT_EXPORT NavigationEntryImpl
                              const PageState& page_state);
 
   // Returns the FrameNavigationEntry corresponding to |frame_tree_node|, if
-  // there is one in this NavigationEntry.
-  FrameNavigationEntry* GetFrameEntry(FrameTreeNode* frame_tree_node) const;
-
-  // Returns the FrameNavigationEntry corresponding to the frame with the given
-  // |unique_name|, if any. This is useful when the FrameTreeNode cannot be used
-  // to find the entry, such as for a newly created subframe in a history
-  // navigation. Callers should update the FrameTreeNode ID of the entry so that
-  // it can be found with |GetFrameEntry| above.
-  // TODO(creis): Generate or verify the unique_name in the browser process.
-  FrameNavigationEntry* GetFrameEntryByUniqueName(
-      const std::string& unique_name) const;
+  // there is one in this NavigationEntry. This compares against the
+  // FrameTreeNode ID first, and if that doesn't match, then the unique_name.
+  // It will update the FrameNavigationEntry's FrameTreeNode ID if it is stale.
+  FrameNavigationEntry* GetFrameEntry(FrameTreeNode* frame_tree_node);
 
   void set_unique_id(int unique_id) {
     unique_id_ = unique_id;
@@ -364,8 +359,7 @@ class CONTENT_EXPORT NavigationEntryImpl
 
  private:
   // Finds the TreeNode associated with |frame_tree_node|, if any.
-  NavigationEntryImpl::TreeNode* FindFrameEntry(
-      FrameTreeNode* frame_tree_node) const;
+  NavigationEntryImpl::TreeNode* FindFrameEntry(FrameTreeNode* frame_tree_node);
 
   // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
   // Session/Tab restore save portions of this class so that it can be recreated