Add taskid for navigation, created in session sync

components/sessions/core/serialized_navigation_entry.h

Index: components/sessions/core/serialized_navigation_entry.h
diff --git a/components/sessions/core/serialized_navigation_entry.h b/components/sessions/core/serialized_navigation_entry.h
index 3a8e665ff02e256d5e8ab330a1ccef226e3c4813..d836d73c112486c8cc5fdd1814bfa92ce0054a44 100644
--- a/components/sessions/core/serialized_navigation_entry.h
+++ b/components/sessions/core/serialized_navigation_entry.h
@@ -128,6 +128,9 @@ class SESSIONS_EXPORT SerializedNavigationEntry {
     return extended_info_map_;
   }
 
+  const std::vector<int64_t>& get_task_id() const { return task_id_; }
+  void set_task_id(const std::vector<int64_t>& task_id) { task_id_ = task_id; }
+
   size_t EstimateMemoryUsage() const;
 
  private:
@@ -169,6 +172,9 @@ class SESSIONS_EXPORT SerializedNavigationEntry {
   // Provides storage for arbitrary key/value pairs used by features. This
   // data is not synced.
   std::map<std::string, std::string> extended_info_map_;
+
+  // Task id of a Chrome task, which is prefixed by its parent task.

[Patrick Noland, 2017/03/24 20:51:57]

Can you explain the prefixing more fully; i.e. it's not prefixed by just its
parent, but all the way up to the root.

[shenchao, 2017/03/25 23:53:13]

Move it above to the variables corresponding to NavigationEntry fields, so
people can go to proto to see explanation

+  std::vector<int64_t> task_id_;
 };
 
 }  // namespace sessions