Replace unique_ptr.reset(other_unique_ptr.release()) with std::move() in cc/trees/

cc/trees/layer_tree_impl_unittest.cc

Index: cc/trees/layer_tree_impl_unittest.cc
diff --git a/cc/trees/layer_tree_impl_unittest.cc b/cc/trees/layer_tree_impl_unittest.cc
index ed081140326e824d072f320ae7b6fe48e6ad8620..d25530103e99f5c2b36917cefd2e0de6d476a505 100644
--- a/cc/trees/layer_tree_impl_unittest.cc
+++ b/cc/trees/layer_tree_impl_unittest.cc
@@ -1073,7 +1073,7 @@ TEST_F(LayerTreeImplTest, HitTestingRespectsClipParents) {
     std::unique_ptr<std::set<LayerImpl*>> clip_children(
         new std::set<LayerImpl*>);
     clip_children->insert(grand_child.get());
-    root->test_properties()->clip_children.reset(clip_children.release());
+    root->test_properties()->clip_children = std::move(clip_children);
 
     child->test_properties()->AddChild(std::move(grand_child));
     root->test_properties()->AddChild(std::move(child));