Scroll with Layers in views::ScrollView

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 0e7a56fda49ef48a16d81796ecafb6443f98f697..68917861bc394e66377513ce51794d4d8fa8c511 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -627,6 +627,27 @@ ScrollElasticityHelper* LayerTreeHostImpl::CreateScrollElasticityHelper() {
   return scroll_elasticity_helper_.get();
 }
 
+bool LayerTreeHostImpl::GetScrollOffsetForLayer(int layer_id,
+                                                gfx::ScrollOffset* offset) {
+  LayerImpl* layer = active_tree()->FindActiveTreeLayerById(layer_id);
+  if (!layer)
+    return false;
+
+  *offset = layer->CurrentScrollOffset();
+  return true;
+}
+
+bool LayerTreeHostImpl::ScrollLayerTo(int layer_id,
+                                      const gfx::ScrollOffset& offset) {
+  LayerImpl* layer = active_tree()->FindActiveTreeLayerById(layer_id);
+  if (!layer)
+    return false;
+
+  layer->ScrollBy(
+      ScrollOffsetToVector2dF(offset - layer->CurrentScrollOffset()));
+  return true;
+}
+
 void LayerTreeHostImpl::QueueSwapPromiseForMainThreadScrollUpdate(
     std::unique_ptr<SwapPromise> swap_promise) {
   swap_promises_for_main_thread_scroll_update_.push_back(