Take MT jank into account when animating the scroll offset on CC

cc/trees/layer_tree_host_impl.h

 // Copyright 2011 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.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_IMPL_H_
 #define CC_TREES_LAYER_TREE_HOST_IMPL_H_
 
 #include <stddef.h>
 
 #include <bitset>
@@ skipping 710 matching lines @@
   void NotifySwapPromiseMonitorsOfSetNeedsRedraw();
   void NotifySwapPromiseMonitorsOfForwardingToMainThread();
 
   void UpdateRootLayerStateForSynchronousInputHandler();
 
   void ScrollAnimationAbort(LayerImpl* layer_impl);
 
   bool ScrollAnimationUpdateTarget(ScrollNode* scroll_node,
                                    const gfx::Vector2dF& scroll_delta);
 
+  void AdjustDuration(base::TimeDelta adjustment) override;
+
   using UIResourceMap = std::unordered_map<UIResourceId, UIResourceData>;
   UIResourceMap ui_resource_map_;
 
   // Resources that were evicted by EvictAllUIResources. Resources are removed
   // from this when they are touched by a create or destroy from the UI resource
   // request queue.
   std::set<UIResourceId> evicted_ui_resources_;
 
   OutputSurface* output_surface_;
 
@@ skipping 119 matching lines @@
       fixed_raster_scale_attempted_scale_change_history_;
   std::unique_ptr<PendingTreeDurationHistogramTimer>
       pending_tree_duration_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_