Create FrameNavigationEntries for manual subframe navigations.

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 8c3fbb5226c8a053583cf98c3ed0cec68ab707fc..6fd931a349e888678cdc45f677b630abf9810cba 100644
--- a/content/browser/frame_host/navigation_entry_impl.h
+++ b/content/browser/frame_host/navigation_entry_impl.h
@@ -28,18 +28,25 @@ class CONTENT_EXPORT NavigationEntryImpl
     : public NON_EXPORTED_BASE(NavigationEntry) {
  public:
   // Represents a tree of FrameNavigationEntries that make up this joint session
-  // history item.  The tree currently only tracks the main frame.
-  // TODO(creis): Populate the tree with subframe entries in --site-per-process.
+  // history item.  The tree currently only tracks the main frame by default,
+  // and is populated with subframe nodes in --site-per-process mode.
   struct TreeNode {
     TreeNode(FrameNavigationEntry* frame_entry);
     ~TreeNode();
 
+    // Returns whether this TreeNode corresponds to |frame_tree_node|.
+    bool MatchesFrame(FrameTreeNode* frame_tree_node) const;
+
     // Returns a deep copy of the tree with copies of each node's
-    // FrameNavigationEntries.  We do not yet share FrameNavigationEntries
-    // across trees.
+    // FrameNavigationEntries.  Replaces the TreeNode corresponding to
+    // |frame_tree_node| (and all of its children) with a new TreeNode for
+    // |frame_navigation_entry|.  Pass nullptr for both for a complete clone.

[Avi (use Gerrit), 2015/05/19 16:34:13]

I'm pondering this comment.

1. "with copies of each node's FNEs". We're not making copies, though, we're
sharing the the FNEs with ref-counted pointers, right?

2. "of the tree" meaning the tree rooted at this entry?

[Charlie Reis, 2015/05/19 17:59:24]

We're not sharing FNEs just yet (hence the TODO below).  I decided to postpone
that to another CL since it affects cloning tabs, session restore, etc.  Easier
to just have each tree have its own set of FNEs for the moment, and then we can
start sharing them.
Agreed, this part is confusing, since the comment is on TreeNode but is phrased
as the whole tree.  I've rephrased it.

+    //
     // TODO(creis): For --site-per-process, share FrameNavigationEntries between
     // NavigationEntries of the same tab.
-    TreeNode* Clone() const;
+    TreeNode* CloneAndReplace(
+        FrameTreeNode* frame_tree_node,
+        FrameNavigationEntry* frame_navigation_entry) const;
 
     // Ref counted pointer that keeps the FrameNavigationEntry alive as long as
     // it is needed by this node's NavigationEntry.
@@ -119,11 +126,16 @@ class CONTENT_EXPORT NavigationEntryImpl
   // Creates a copy of this NavigationEntryImpl that can be modified
   // independently from the original.  Does not copy any value that would be
   // cleared in ResetForCommit.
+  NavigationEntryImpl* Clone() const;
+
+  // Like |Clone|, but replaces the FrameNavigationEntry corresponding to
+  // |frame_tree_node| (and all its children) with |frame_entry|.
   // TODO(creis): Once we start sharing FrameNavigationEntries between
   // NavigationEntryImpls, we will need to support two versions of Clone: one
   // that shares the existing FrameNavigationEntries (for use within the same
   // tab) and one that draws them from a different pool (for use in a new tab).
-  NavigationEntryImpl* Clone() const;
+  NavigationEntryImpl* CloneAndReplace(FrameTreeNode* frame_tree_node,
+                                       FrameNavigationEntry* frame_entry) const;
 
   // Helper functions to construct NavigationParameters for a navigation to this
   // NavigationEntry.