Add the navigation redirect-chain to Sync sessions proto for offline analysis.

content/browser/frame_host/navigation_controller_impl.h

Index: content/browser/frame_host/navigation_controller_impl.h
diff --git a/content/browser/frame_host/navigation_controller_impl.h b/content/browser/frame_host/navigation_controller_impl.h
index a33f5bccd7a4c24737b40c882a1525fd3c2994ea..ce9e90a7f20549cb0aa3683f09029f695b61e2fc 100644
--- a/content/browser/frame_host/navigation_controller_impl.h
+++ b/content/browser/frame_host/navigation_controller_impl.h
@@ -209,6 +209,13 @@ class CONTENT_EXPORT NavigationControllerImpl
   // Discards only the pending entry.
   void DiscardPendingEntry();
 
+  // Produces a redirect chain by merging the active entry redirects with the
+  // redirects given in the params, taking into account the type of navigation
+  // specified in the params.
+  std::vector<GURL> GetMergedRedirectChain(
+      const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
+      const std::vector<GURL>& active_entry_redirects) const;
+
  private:
   friend class RestoreHelper;