Manage registering composited elements in PaintArtifactCompositor.

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp

 // Copyright 2015 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 "platform/graphics/compositing/PaintArtifactCompositor.h"
 
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/picture_layer.h"
 #include "cc/paint/display_item_list.h"
 #include "cc/trees/layer_tree_host.h"
+#include "cc/trees/mutator_host_client.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/compositing/PaintChunksToCcLayer.h"
 #include "platform/graphics/compositing/PropertyTreeManager.h"
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "platform/graphics/paint/ForeignLayerDisplayItem.h"
 #include "platform/graphics/paint/GeometryMapper.h"
 #include "platform/graphics/paint/PaintArtifact.h"
 #include "platform/graphics/paint/PropertyTreeState.h"
@@ skipping 627 matching lines @@
     layer->set_offset_to_transform_parent(layer_offset);
     CompositorElementId element_id =
         pending_layer.property_tree_state.GetCompositorElementId(
             composited_element_ids);
     if (element_id) {
       layer->SetElementId(element_id);
       composited_element_ids.insert(element_id);
     }
 
     root_layer_->AddChild(layer);
+    if (auto previous_host = layer->layer_tree_host()) {
+      previous_host->UnregisterElement(element_id, cc::ElementListType::ACTIVE,
+                                       layer.get());
+    }
+    if (element_id) {
+      auto host = root_layer_->layer_tree_host();
+      host->RegisterElement(element_id, cc::ElementListType::ACTIVE,
+                            layer.get());
+      if (host->mutator_host()->HasAnyAnimation(element_id))

[wkorman, 2017/05/17 20:07:50]

Believe we actually don't need to do this in SPv2, removed in latest patch set.
We appear to SetNeedsCommit on the LTH every time Update is called.

+        host->SetNeedsCommit();
+    }
+
     layer->set_property_tree_sequence_number(g_s_property_tree_sequence_number);
     layer->SetTransformTreeIndex(transform_id);
     layer->SetClipTreeIndex(clip_id);
     layer->SetEffectTreeIndex(effect_id);
     property_tree_manager.UpdateLayerScrollMapping(layer.get(), transform);
 
     layer->SetShouldCheckBackfaceVisibility(pending_layer.backface_hidden);
 
     if (extra_data_for_testing_enabled_)
       extra_data_for_testing_->content_layers.push_back(layer);
@@ skipping 13 matching lines @@
 #ifndef NDEBUG
 void PaintArtifactCompositor::ShowDebugData() {
   LOG(ERROR) << LayersAsJSON(kLayerTreeIncludesDebugInfo)
                     ->ToPrettyJSONString()
                     .Utf8()
                     .data();
 }
 #endif
 
 }  // namespace blink