DRAFT CL: Add FrameNavigationEntry and track subframe session histories.

content/browser/frame_host/navigation_controller_delegate.h

Index: content/browser/frame_host/navigation_controller_delegate.h
diff --git a/content/browser/frame_host/navigation_controller_delegate.h b/content/browser/frame_host/navigation_controller_delegate.h
index e578a84e9126608e98a4a6cdd54562e5bcfdecbf..ce8c7eac01f846f1f1e36f68dab1c0edec144d20 100644
--- a/content/browser/frame_host/navigation_controller_delegate.h
+++ b/content/browser/frame_host/navigation_controller_delegate.h
@@ -15,6 +15,7 @@ namespace content {
 struct LoadCommittedDetails;
 struct LoadNotificationDetails;
 struct NativeWebKeyboardEvent;
+class FrameTreeNode;
 class InterstitialPage;
 class InterstitialPageImpl;
 class RenderFrameHost;
@@ -49,8 +50,6 @@ class NavigationControllerDelegate {
   virtual void NotifyBeforeFormRepostWarningShow() = 0;
   virtual void NotifyNavigationEntryCommitted(
       const LoadCommittedDetails& load_details) = 0;
-  virtual bool NavigateToPendingEntry(
-      NavigationController::ReloadType reload_type) = 0;
   virtual void SetHistoryOffsetAndLength(int history_offset,
                                          int history_length) = 0;
   virtual void CopyMaxPageIDsFrom(WebContents* web_contents) = 0;
@@ -64,6 +63,8 @@ class NavigationControllerDelegate {
   // embedder for NavigationController will be a WebContents object.
   virtual WebContents* GetWebContents() = 0;
 
+  virtual FrameTreeNode* GetFrameTreeRoot() = 0;
+
   // Methods needed by InterstitialPageImpl.
   virtual bool IsHidden() = 0;
   virtual void RenderFrameForInterstitialPageCreated(