Reland: Update cc layers when collecting layer tree for devtools

We use cc::Layer::ScreenSpaceTransform() when collecting layer tree
for devtools in layer list mode. We need to ensure the screen space
transforms are up-to-date before using them.

This is a reland of https://crrev.com/671720 which was rolled out in
https://crrev.com/677720 due to multiple UpdateLayers calls. Full layer
updates (e.g., with invalidation) are not needed for up-to-date
to-screen transforms.

Bug: 977578
Change-Id: I21a39a4198290c64e315c586c64a4da3a83da83d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1720791Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681382}

cc/trees/layer_tree_host.cc

@@ -716,6 +716,10 @@ bool LayerTreeHost::UpdateLayers() {
   return result;
 }
 
+void LayerTreeHost::UpdatePropertyTrees() {
+  draw_property_utils::UpdatePropertyTrees(this, &property_trees_);
+}
+
 void LayerTreeHost::DidPresentCompositorFrame(
     uint32_t frame_token,
     std::vector<LayerTreeHost::PresentationTimeCallback> callbacks,
@@ -847,7 +851,7 @@ bool LayerTreeHost::DoUpdateLayers() {
   CHECK(property_trees_.effect_tree.Node(root_layer_->effect_tree_index()));
 #endif
 
-  draw_property_utils::UpdatePropertyTrees(this, &property_trees_);
+  UpdatePropertyTrees();
 
   LayerList update_layer_list;
   draw_property_utils::FindLayersThatNeedUpdates(this, &property_trees_,

cc/trees/layer_tree_host.h

@@ -586,6 +586,7 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
     client_->DidReceiveCompositorFrameAck();
   }
   bool UpdateLayers();
+  void UpdatePropertyTrees();
   void DidPresentCompositorFrame(
       uint32_t frame_token,
       std::vector<LayerTreeHost::PresentationTimeCallback> callbacks,

third_party/blink/renderer/core/inspector/inspector_layer_tree_agent.cc

@@ -173,13 +173,16 @@ BuildStickyInfoForLayer(const cc::Layer* root, const cc::Layer* layer) {
   return constraints_obj;
 }
 
+static bool IsUsingLayerLists(const cc::Layer* root) {
+  return root->layer_tree_host() &&
+         root->layer_tree_host()->IsUsingLayerLists();
+}
+
 static std::unique_ptr<protocol::LayerTree::Layer> BuildObjectForLayer(
     const cc::Layer* root,
     const cc::Layer* layer,
     bool report_wheel_event_listeners) {
-  bool using_layer_list =
-      RuntimeEnabledFeatures::CompositeAfterPaintEnabled() ||
-      RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled();
+  bool is_using_layer_lists = IsUsingLayerLists(root);
 
   // When the front-end doesn't show internal layers, it will use the the first
   // DrawsContent layer as the root of the shown layer tree. This doesn't work
@@ -187,13 +190,13 @@ static std::unique_ptr<protocol::LayerTree::Layer> BuildObjectForLayer(
   // all DrawsContent layers. We have to cheat the front-end by setting
   // drawsContent to true for the root layer.
   bool draws_content =
-      (using_layer_list && root == layer) || layer->DrawsContent();
+      (is_using_layer_lists && root == layer) || layer->DrawsContent();
 
   std::unique_ptr<protocol::LayerTree::Layer> layer_object =
       protocol::LayerTree::Layer::create()
           .setLayerId(IdForLayer(layer))
-          .setOffsetX(using_layer_list ? 0 : layer->position().x())
-          .setOffsetY(using_layer_list ? 0 : layer->position().y())
+          .setOffsetX(is_using_layer_lists ? 0 : layer->position().x())
+          .setOffsetY(is_using_layer_lists ? 0 : layer->position().y())
           .setWidth(layer->bounds().width())
           .setHeight(layer->bounds().height())
           .setPaintCount(layer->paint_count())
@@ -208,7 +211,7 @@ static std::unique_ptr<protocol::LayerTree::Layer> BuildObjectForLayer(
 
   gfx::Transform transform;
   gfx::Point3F transform_origin;
-  if (using_layer_list) {
+  if (is_using_layer_lists) {
     transform = layer->ScreenSpaceTransform();
   } else {
     transform = layer->transform();
@@ -348,6 +351,11 @@ InspectorLayerTreeAgent::BuildLayerTree() {
           root_frame, cc::EventListenerClass::kMouseWheel) ==
       cc::EventListenerProperties::kBlocking;
 
+  if (IsUsingLayerLists(root_layer)) {
+    // The property trees must be updated for correct screen space transforms.
+    root_layer->layer_tree_host()->UpdatePropertyTrees();
+  }
+
   GatherLayers(root_layer, layers, have_blocking_wheel_event_handlers,
                scrolling_layer_id);
   return layers;

third_party/blink/web_tests/http/tests/devtools/layers/layers-3d-view-hit-testing.js

@@ -5,6 +5,7 @@
 (async function() {
   TestRunner.addResult(`Tests hit testing in Layers3DView\n`);
   await TestRunner.loadModule('layers_test_runner');
+  await TestRunner.showPanel('layers');
 
   await TestRunner.loadHTML(`
       <div id="a" style="transform:translateZ(0px) translateY(60px) rotateZ(45deg);width:300px;height:300px;margin-left:100px; border: 1px solid black;">
@@ -18,7 +19,6 @@
   var canvas;
   const ButtonByEventType = {mousemove: -1, mousedown: 0, mouseup: 0};
 
-  TestRunner.showPanel('layers');
   await LayersTestRunner.requestLayers();
   initLayers();
   initSizes();