Introduce LayerListImpl

In this cl, the LayerTreeImpl constructs a LayerListImpl.
The idea being that most plumbing won't need to change at
first to get the list to where it needs to be. The first
consumer of the LayerTreeImpl that I'm attempting to
teach to speak LayerListImpl-ese is the LayerImpl. That
has not been completely finished in this cl so that it
doesn't become too big and difficult to review.

NB: since the actual storage of the LayerImpls doesn't
change in this cl (they're still in the LayerTreeImpl),
there's no need to guard this work behind a flag.

BUG=557194
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1746603002

Cr-Commit-Position: refs/heads/master@{#378398}

1 files changed, 22 insertions, 27 deletions

diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index ae14d9c..3f14de8 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -56,6 +56,7 @@ LayerImpl::LayerImpl(LayerTreeImpl* tree_impl,
       replica_layer_id_(-1),
       layer_id_(id),
       layer_tree_impl_(tree_impl),
+      layer_list_impl_(tree_impl->list()),
       scroll_offset_(scroll_offset),
       scroll_clip_layer_id_(Layer::INVALID_ID),
       main_thread_scrolling_reasons_(
@@ -102,11 +103,10 @@ LayerImpl::LayerImpl(LayerTreeImpl* tree_impl,
       layer_or_descendant_has_touch_handler_(false),
       sorted_for_recursion_(false) {
   DCHECK_GT(layer_id_, 0);
-  DCHECK(layer_tree_impl_);
-  layer_tree_impl_->RegisterLayer(this);
+  layer_list_impl_->RegisterLayer(this);
 
   if (!layer_tree_impl_->settings().use_compositor_animation_timelines) {
-    AnimationRegistrar* registrar = layer_tree_impl_->GetAnimationRegistrar();
+    AnimationRegistrar* registrar = layer_list_impl_->GetAnimationRegistrar();
     layer_animation_controller_ =
         registrar->GetAnimationControllerForId(layer_id_);
     layer_animation_controller_->AddValueObserver(this);
@@ -116,7 +116,7 @@ LayerImpl::LayerImpl(LayerTreeImpl* tree_impl,
     }
   }
 
-  layer_tree_impl_->AddToElementMap(this);
+  layer_list_impl_->AddToElementMap(this);
 
   SetNeedsPushProperties();
 }
@@ -133,9 +133,9 @@ LayerImpl::~LayerImpl() {
   if (!copy_requests_.empty() && layer_tree_impl_->IsActiveTree())
     layer_tree_impl()->RemoveLayerWithCopyOutputRequest(this);
   layer_tree_impl_->UnregisterScrollLayer(this);
-  layer_tree_impl_->UnregisterLayer(this);
+  layer_list_impl_->UnregisterLayer(this);
 
-  layer_tree_impl_->RemoveFromElementMap(this);
+  layer_list_impl_->RemoveFromElementMap(this);
 
   TRACE_EVENT_OBJECT_DELETED_WITH_ID(
       TRACE_DISABLED_BY_DEFAULT("cc.debug"), "cc::LayerImpl", this);
@@ -197,7 +197,7 @@ void LayerImpl::SetScrollParent(LayerImpl* parent) {
     return;
 
   if (parent)
-    DCHECK_EQ(layer_tree_impl()->LayerById(parent->id()), parent);
+    DCHECK_EQ(layer_list_impl_->LayerById(parent->id()), parent);
 
   scroll_parent_ = parent;
   SetNeedsPushProperties();
@@ -470,13 +470,13 @@ void LayerImpl::SetScrollClipLayer(int scroll_clip_layer_id) {
   if (scroll_clip_layer_id_ == scroll_clip_layer_id)
     return;
 
-  layer_tree_impl()->UnregisterScrollLayer(this);
+  layer_tree_impl_->UnregisterScrollLayer(this);
   scroll_clip_layer_id_ = scroll_clip_layer_id;
-  layer_tree_impl()->RegisterScrollLayer(this);
+  layer_tree_impl_->RegisterScrollLayer(this);
 }
 
 LayerImpl* LayerImpl::scroll_clip_layer() const {
-  return layer_tree_impl()->LayerById(scroll_clip_layer_id_);
+  return layer_list_impl_->LayerById(scroll_clip_layer_id_);
 }
 
 bool LayerImpl::scrollable() const {
@@ -563,7 +563,7 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
 
   LayerImpl* scroll_parent = nullptr;
   if (scroll_parent_) {
-    scroll_parent = layer->layer_tree_impl()->LayerById(scroll_parent_->id());
+    scroll_parent = layer->layer_list_impl_->LayerById(scroll_parent_->id());
     DCHECK(scroll_parent);
   }
 
@@ -574,8 +574,7 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
          it != scroll_children_->end();
          ++it) {
       DCHECK_EQ((*it)->scroll_parent(), this);
-      LayerImpl* scroll_child =
-          layer->layer_tree_impl()->LayerById((*it)->id());
+      LayerImpl* scroll_child = layer->layer_list_impl_->LayerById((*it)->id());
       DCHECK(scroll_child);
       scroll_children->insert(scroll_child);
     }
@@ -586,8 +585,7 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
 
   LayerImpl* clip_parent = nullptr;
   if (clip_parent_) {
-    clip_parent = layer->layer_tree_impl()->LayerById(
-        clip_parent_->id());
+    clip_parent = layer->layer_list_impl_->LayerById(clip_parent_->id());
     DCHECK(clip_parent);
   }
 
@@ -596,7 +594,7 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
     std::set<LayerImpl*>* clip_children = new std::set<LayerImpl*>;
     for (std::set<LayerImpl*>::iterator it = clip_children_->begin();
         it != clip_children_->end(); ++it)
-      clip_children->insert(layer->layer_tree_impl()->LayerById((*it)->id()));
+      clip_children->insert(layer->layer_list_impl_->LayerById((*it)->id()));
     layer->SetClipChildren(clip_children);
   } else {
     layer->SetClipChildren(nullptr);
@@ -635,7 +633,7 @@ bool LayerImpl::IsAffectedByPageScale() const {
 
 gfx::Vector2dF LayerImpl::FixedContainerSizeDelta() const {
   LayerImpl* scroll_clip_layer =
-      layer_tree_impl()->LayerById(scroll_clip_layer_id_);
+      layer_list_impl_->LayerById(scroll_clip_layer_id_);
   if (!scroll_clip_layer)
     return gfx::Vector2dF();
 
@@ -1212,9 +1210,9 @@ void LayerImpl::SetElementId(uint64_t element_id) {
   TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("compositor-worker"),
                "LayerImpl::SetElementId", "id", element_id);
 
-  layer_tree_impl_->RemoveFromElementMap(this);
+  layer_list_impl_->RemoveFromElementMap(this);
   element_id_ = element_id;
-  layer_tree_impl_->AddToElementMap(this);
+  layer_list_impl_->AddToElementMap(this);
   SetNeedsPushProperties();
 }
 
@@ -1227,7 +1225,7 @@ void LayerImpl::SetMutableProperties(uint32_t properties) {
 
   mutable_properties_ = properties;
   // If this layer is already in the element map, update its properties.
-  layer_tree_impl_->AddToElementMap(this);
+  layer_list_impl_->AddToElementMap(this);
   SetNeedsPushProperties();
 }
 
@@ -1486,7 +1484,7 @@ void LayerImpl::PushScrollOffset(const gfx::ScrollOffset* scroll_offset) {
   DCHECK(scroll_offset || IsActive());
   bool changed = false;
   if (scroll_offset) {
-    DCHECK(!IsActive() || !layer_tree_impl_->FindPendingTreeLayerById(id()));
+    DCHECK(!IsActive() || !layer_list_impl_->FindPendingLayerById(id()));
     changed |= scroll_offset_->PushFromMainThread(*scroll_offset);
   }
   if (IsActive()) {
@@ -1523,7 +1521,7 @@ void LayerImpl::DidUpdateScrollOffset() {
 
   // Inform the pending twin that a property changed.
   if (layer_tree_impl()->IsActiveTree()) {
-    LayerImpl* pending_twin = layer_tree_impl()->FindPendingTreeLayerById(id());
+    LayerImpl* pending_twin = layer_list_impl_->FindPendingLayerById(id());
     if (pending_twin)
       pending_twin->DidUpdateScrollOffset();
   }
@@ -1601,11 +1599,8 @@ void LayerImpl::GetAllPrioritizedTilesForTracing(
 
 void LayerImpl::AsValueInto(base::trace_event::TracedValue* state) const {
   TracedValue::MakeDictIntoImplicitSnapshotWithCategory(
-      TRACE_DISABLED_BY_DEFAULT("cc.debug"),
-      state,
-      "cc::LayerImpl",
-      LayerTypeAsString(),
-      this);
+      TRACE_DISABLED_BY_DEFAULT("cc.debug"), state, "cc::LayerImpl",
+      LayerTypeAsString(), this);
   state->SetInteger("layer_id", id());
   MathUtil::AddToTracedValue("bounds", bounds_, state);