Update from https://crrev.com/309717

cc/trees/layer_tree_host_unittest_scroll.cc

Index: cc/trees/layer_tree_host_unittest_scroll.cc
diff --git a/cc/trees/layer_tree_host_unittest_scroll.cc b/cc/trees/layer_tree_host_unittest_scroll.cc
index bd09d6aacb4957d828291fc1d4f2e44100aefecb..4e561ede8b2d23d0eb7aeadfcbc198df2a564e8c 100644
--- a/cc/trees/layer_tree_host_unittest_scroll.cc
+++ b/cc/trees/layer_tree_host_unittest_scroll.cc
@@ -1106,6 +1106,13 @@ class ThreadCheckingInputHandlerClient : public InputHandlerClient {
     *received_stop_flinging_ = true;
   }
 
+  void ReconcileElasticOverscrollAndRootScroll() override {
+    if (!task_runner_->BelongsToCurrentThread()) {
+      ADD_FAILURE() << "ReconcileElasticOverscrollAndRootScroll called on "
+                    << "wrong thread";
+    }
+  }
+
  private:
   base::SingleThreadTaskRunner* task_runner_;
   bool* received_stop_flinging_;