[Sync] Made some sync session member functions const

chrome/browser/sync/engine/store_timestamps_command.cc

Index: chrome/browser/sync/engine/store_timestamps_command.cc
diff --git a/chrome/browser/sync/engine/store_timestamps_command.cc b/chrome/browser/sync/engine/store_timestamps_command.cc
index a063bf4adb20e771a9945b2d3ae5da03622f2f25..62ca90573833a8dcb361f8461abb349f03a1286a 100644
--- a/chrome/browser/sync/engine/store_timestamps_command.cc
+++ b/chrome/browser/sync/engine/store_timestamps_command.cc
@@ -25,9 +25,9 @@ void StoreTimestampsCommand::ExecuteImpl(sessions::SyncSession* session) {
   }
 
   const GetUpdatesResponse& updates =
-      session->status_controller()->updates_response().get_updates();
+      session->status_controller().updates_response().get_updates();
 
-  sessions::StatusController* status = session->status_controller();
+  sessions::StatusController* status = session->mutable_status_controller();
 
   // Update the progress marker tokens from the server result.  If a marker
   // was omitted for any one type, that indicates no change from the previous