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..1fdfd7cd8bf258842efdf35ec7f3bb1d03e2e083 100644
--- a/content/browser/frame_host/navigation_controller_impl.h
+++ b/content/browser/frame_host/navigation_controller_impl.h
@@ -214,6 +214,16 @@ class CONTENT_EXPORT NavigationControllerImpl
 
   FRIEND_TEST_ALL_PREFIXES(NavigationControllerTest,
                            PurgeScreenshot);
+  FRIEND_TEST_ALL_PREFIXES(NavigationControllerTest,
+                           GetMergedRedirectChainNewPage);
+  FRIEND_TEST_ALL_PREFIXES(NavigationControllerTest,
+                           GetMergedRedirectChainSamePage);
+  FRIEND_TEST_ALL_PREFIXES(NavigationControllerTest,
+                           GetMergedRedirectChainMergeNoOverlap);
+  FRIEND_TEST_ALL_PREFIXES(NavigationControllerTest,
+                           GetMergedRedirectChainMergeOneOverlap);
+  FRIEND_TEST_ALL_PREFIXES(NavigationControllerTest,
+                           GetMergedRedirectChainMergeTwoOverlap);
   FRIEND_TEST_ALL_PREFIXES(TimeSmoother, Basic);
   FRIEND_TEST_ALL_PREFIXES(TimeSmoother, SingleDuplicate);
   FRIEND_TEST_ALL_PREFIXES(TimeSmoother, ManyDuplicates);
@@ -336,6 +346,13 @@ class CONTENT_EXPORT NavigationControllerImpl
   // specified |offset|.  The index returned is not guaranteed to be valid.
   int GetIndexForOffset(int offset) const;
 
+  // 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;
+
   // ---------------------------------------------------------------------------
 
   // The user browser context associated with this controller.