[SPv2] Build trivial cc property trees in PaintArtifactCompositor.

cc/trees/layer_tree_host.cc

 // 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.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 970 matching lines @@
 
   gfx::Transform identity_transform;
   LayerList update_layer_list;
 
   {
     TRACE_EVENT0("cc", "LayerTreeHost::UpdateLayers::BuildPropertyTrees");
     TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cc.debug.cdp-perf"),
                  "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);
     draw_property_utils::FindLayersThatNeedUpdates(
         this, property_trees_.transform_tree, property_trees_.effect_tree,
         &update_layer_list);
   }
 
   for (const auto& layer : update_layer_list)
     layer->SavePaintProperties();
@@ skipping 628 matching lines @@
   int seq_num = property_trees_.sequence_number;
   LayerTreeHostCommon::CallFunctionForEveryLayer(this, [seq_num](Layer* layer) {
     layer->set_property_tree_sequence_number(seq_num);
   });
 
   surface_id_namespace_ = proto.surface_id_namespace();
   next_surface_sequence_ = proto.next_surface_sequence();
 }
 
 }  // namespace cc