Update from https://crrev.com/309717

cc/trees/layer_tree_host_unittest_scroll.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include "base/memory/weak_ptr.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/picture_layer.h"
@@ skipping 1088 matching lines @@
     if (!task_runner_->BelongsToCurrentThread())
       ADD_FAILURE() << "Animate called on wrong thread";
   }
 
   void MainThreadHasStoppedFlinging() override {
     if (!task_runner_->BelongsToCurrentThread())
       ADD_FAILURE() << "MainThreadHasStoppedFlinging called on wrong thread";
     *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_;
 };
 
 void BindInputHandlerOnCompositorThread(
     const base::WeakPtr<InputHandler>& input_handler,
     ThreadCheckingInputHandlerClient* client) {
   input_handler->BindToClient(client);
 }
@@ skipping 120 matching lines @@
   RunTest(true, false, true);
 }
 
 TEST_F(LayerTreeHostScrollTestLayerStructureChange, ScrollDestroyWholeTree) {
   scroll_destroy_whole_tree_ = true;
   RunTest(true, false, true);
 }
 
 }  // namespace
 }  // namespace cc