Compute if a layer is drawn without LayerTree hierarchy

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index b845968c2f7df709585ad96bda4ce3ecc1bacc71..6a0b519520b1eb87cc8d7021ae359dc864b66fd6 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -73,7 +73,6 @@ LayerImpl::LayerImpl(LayerTreeImpl* tree_impl,
       is_root_for_isolated_group_(false),
       use_parent_backface_visibility_(false),
       draws_content_(false),
-      hide_layer_and_subtree_(false),
       transform_is_invertible_(true),
       is_container_for_fixed_position_layers_(false),
       is_affected_by_page_scale_(true),
@@ -98,8 +97,7 @@ LayerImpl::LayerImpl(LayerTreeImpl* tree_impl,
       visited_(false),
       layer_or_descendant_is_drawn_(false),
       layer_or_descendant_has_input_handler_(false),
-      sorted_for_recursion_(false),
-      is_hidden_from_property_trees_(false) {
+      sorted_for_recursion_(false) {
   DCHECK_GT(layer_id_, 0);
   DCHECK(layer_tree_impl_);
   layer_tree_impl_->RegisterLayer(this);
@@ -582,7 +580,6 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
   layer->SetBounds(bounds_);
   layer->SetDoubleSided(double_sided_);
   layer->SetDrawsContent(DrawsContent());
-  layer->SetHideLayerAndSubtree(hide_layer_and_subtree_);
   // If whether layer has render surface changes, we need to update draw
   // properties.
   // TODO(weiliangc): Should be safely removed after impl side is able to
@@ -632,7 +629,6 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
   layer->SetClipTreeIndex(clip_tree_index_);
   layer->SetEffectTreeIndex(effect_tree_index_);
   layer->set_offset_to_transform_parent(offset_to_transform_parent_);
-  layer->set_is_hidden_from_property_trees(is_hidden_from_property_trees_);
 
   LayerImpl* scroll_parent = nullptr;
   if (scroll_parent_) {
@@ -1109,14 +1105,6 @@ void LayerImpl::SetDrawsContent(bool draws_content) {
   NoteLayerPropertyChanged();
 }
 
-void LayerImpl::SetHideLayerAndSubtree(bool hide) {
-  if (hide_layer_and_subtree_ == hide)
-    return;
-
-  hide_layer_and_subtree_ = hide;
-  NoteLayerPropertyChangedForSubtree();
-}
-
 void LayerImpl::SetTransformOrigin(const gfx::Point3F& transform_origin) {
   if (transform_origin_ == transform_origin)
     return;
@@ -1896,14 +1884,31 @@ gfx::Rect LayerImpl::GetScaledEnclosingRectInTargetSpace(float scale) const {
                                            gfx::Rect(scaled_bounds));
 }
 
-bool LayerImpl::LayerIsHidden() const {
+bool LayerImpl::IsHidden() const {
   if (layer_tree_impl()->settings().use_property_trees) {
-    return is_hidden_from_property_trees_;
+    EffectTree& effect_tree = layer_tree_impl_->property_trees()->effect_tree;
+    EffectNode* node = effect_tree.Node(effect_tree_index_);
+    return node->data.screen_space_opacity == 0.f;
   } else {
-    return hide_layer_and_subtree_ || (parent() && parent()->LayerIsHidden());
+    return opacity_ == 0.f || (parent() && parent()->IsHidden());
   }
 }
 
+bool LayerImpl::IsDrawnFromPropertyTrees() const {
+  // Layers that have screen space opacity are hidden. So they are not drawn.

[ajuma, 2016/01/15 15:02:46]

"screen space opacity 0"

[jaydasika, 2016/01/19 20:02:49]

Done.

+  // Exceptions:
+  // 1) Layers that contribute to copy requests, whether hidden or not, must be
+  //    drawn.
+  // 2) Layers that have a background filter or an animating opacity.
+  if (HasPotentiallyRunningOpacityAnimation() ||

[ajuma, 2016/01/15 15:02:46]

Do we need the animation check on the compositor side? It makes sense on the
main thread since we can't predict what the opacity will be on the compositor
thread, but on the compositor side we know the current opacity.

[jaydasika, 2016/01/15 18:23:05]

Won't we need it to handle animating opacity on the pending tree ?

[ajuma, 2016/01/15 18:48:16]

Ah, good point.

+      !background_filters().IsEmpty())
+    return true;
+  EffectTree& effect_tree = layer_tree_impl_->property_trees()->effect_tree;
+  EffectNode* node = effect_tree.Node(effect_tree_index_);
+  return node->data.screen_space_opacity != 0.f ||
+         node->data.contributes_to_copy_request;
+}
+
 float LayerImpl::GetIdealContentsScale() const {
   float page_scale = IsAffectedByPageScale()
                          ? layer_tree_impl()->current_page_scale_factor()