[SPv2] Build trivial cc property trees in PaintArtifactCompositor.

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index f41bc9fea43e116e44e5cb744e9d05c65199a90c..8a185be41be39781254c0f89767fddaaba6e524f 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -988,14 +988,21 @@ bool LayerTreeHost::DoUpdateLayers(Layer* root_layer) {
                  "LayerTreeHostCommon::ComputeVisibleRectsWithPropertyTrees");
     PropertyTreeBuilder::PreCalculateMetaInformation(root_layer);
     bool can_render_to_separate_surface = true;
-    PropertyTreeBuilder::BuildPropertyTrees(
-        root_layer, page_scale_layer, inner_viewport_scroll_layer_.get(),
-        outer_viewport_scroll_layer_.get(), overscroll_elasticity_layer_.get(),
-        elastic_overscroll_, page_scale_factor_, device_scale_factor_,
-        gfx::Rect(device_viewport_size_), identity_transform, &property_trees_);
-    TRACE_EVENT_INSTANT1("cc", "LayerTreeHost::UpdateLayers_BuiltPropertyTrees",
-                         TRACE_EVENT_SCOPE_THREAD, "property_trees",
-                         property_trees_.AsTracedValue());
+    if (!settings_.use_layer_lists) {
+      // If use_layer_lists is set, then the property trees should have been
+      // built by the client already.
+      PropertyTreeBuilder::BuildPropertyTrees(
+          root_layer, page_scale_layer, inner_viewport_scroll_layer_.get(),
+          outer_viewport_scroll_layer_.get(),
+          overscroll_elasticity_layer_.get(), elastic_overscroll_,
+          page_scale_factor_, device_scale_factor_,
+          gfx::Rect(device_viewport_size_), identity_transform,
+          &property_trees_);
+      TRACE_EVENT_INSTANT1("cc",
+                           "LayerTreeHost::UpdateLayers_BuiltPropertyTrees",
+                           TRACE_EVENT_SCOPE_THREAD, "property_trees",
+                           property_trees_.AsTracedValue());
+    }
     draw_property_utils::UpdateRenderSurfaces(root_layer, &property_trees_);
     draw_property_utils::UpdatePropertyTrees(&property_trees_,
                                              can_render_to_separate_surface);