DRAFT CL: Add FrameNavigationEntry and track subframe session histories.

content/browser/frame_host/render_frame_host_manager.h

Index: content/browser/frame_host/render_frame_host_manager.h
diff --git a/content/browser/frame_host/render_frame_host_manager.h b/content/browser/frame_host/render_frame_host_manager.h
index f7c15e2bc63fbb2a350fbb1981a4dac184927def..519fe648f65a2be972dda38f2fd8d8b1f236bb3a 100644
--- a/content/browser/frame_host/render_frame_host_manager.h
+++ b/content/browser/frame_host/render_frame_host_manager.h
@@ -26,6 +26,7 @@ namespace content {
 class BrowserContext;
 class CrossProcessFrameConnector;
 class CrossSiteTransferringRequest;
+class FrameNavigationEntry;
 class FrameTreeNode;
 class InterstitialPageImpl;
 class NavigationControllerImpl;
@@ -250,7 +251,12 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
   // navigation entry. It may create a new RenderFrameHost or re-use an existing
   // one. The RenderFrameHost to navigate will be returned. Returns NULL if one
   // could not be created.
-  RenderFrameHostImpl* Navigate(const NavigationEntryImpl& entry);
+  RenderFrameHostImpl* Navigate(const FrameNavigationEntry& frame_entry,
+                                const NavigationEntryImpl& entry);
+
+  // Convenience function for the main frame's RenderFrameHostManager, which
+  // navigates to the root FrameNavigationEntry for |entry|.
+  RenderFrameHostImpl* NavigateMainFrame(const NavigationEntryImpl& entry);
 
   // Instructs the various live views to stop. Called when the user directed the
   // page to stop loading.