Compute if a layer is drawn without LayerTree hierarchy

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index 9fa27317b5bd4d3b6f48c4f15c456865d2c87ffd..e9c222b0ae8b035924881043f85206b6737317ff 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -77,7 +77,6 @@ Layer::Layer(const LayerSettings& settings)
       is_container_for_fixed_position_layers_(false),
       is_drawable_(false),
       draws_content_(false),
-      hide_layer_and_subtree_(false),
       masks_to_bounds_(false),
       contents_opaque_(false),
       double_sided_(true),
@@ -99,8 +98,7 @@ Layer::Layer(const LayerSettings& settings)
       replica_layer_(nullptr),
       client_(nullptr),
       num_unclipped_descendants_(0),
-      frame_timing_requests_dirty_(false),
-      is_hidden_from_property_trees_(false) {
+      frame_timing_requests_dirty_(false) {
   if (!settings.use_compositor_animation_timelines) {
     layer_animation_controller_ = LayerAnimationController::Create(layer_id_);
     layer_animation_controller_->AddValueObserver(this);
@@ -1097,15 +1095,6 @@ void Layer::SetIsDrawable(bool is_drawable) {
   UpdateDrawsContent(HasDrawableContent());
 }
 
-void Layer::SetHideLayerAndSubtree(bool hide) {
-  DCHECK(IsPropertyChangeAllowed());
-  if (hide_layer_and_subtree_ == hide)
-    return;
-
-  hide_layer_and_subtree_ = hide;
-  SetNeedsCommit();
-}
-
 void Layer::SetNeedsDisplayRect(const gfx::Rect& dirty_rect) {
   if (dirty_rect.IsEmpty())
     return;
@@ -1188,7 +1177,6 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
   layer->set_offset_to_transform_parent(offset_to_transform_parent_);
   layer->SetDoubleSided(double_sided_);
   layer->SetDrawsContent(DrawsContent());
-  layer->SetHideLayerAndSubtree(hide_layer_and_subtree_);
   layer->SetHasRenderSurface(has_render_surface_);
   layer->SetForceRenderSurface(force_render_surface_);
   if (!layer->FilterIsAnimatingOnImplOnly() && !FilterIsAnimating())
@@ -1228,7 +1216,6 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
   layer->set_user_scrollable_vertical(user_scrollable_vertical_);
   layer->SetElementId(element_id_);
   layer->SetMutableProperties(mutable_properties_);
-  layer->set_is_hidden_from_property_trees(is_hidden_from_property_trees_);
 
   LayerImpl* scroll_parent = nullptr;
   if (scroll_parent_) {
@@ -1458,7 +1445,6 @@ void Layer::LayerSpecificPropertiesToProto(proto::LayerProperties* proto) {
                    base->mutable_offset_to_transform_parent());
   base->set_double_sided(double_sided_);
   base->set_draws_content(draws_content_);
-  base->set_hide_layer_and_subtree(hide_layer_and_subtree_);
   base->set_has_render_surface(has_render_surface_);
 
   // TODO(nyquist): Add support for serializing FilterOperations for
@@ -1548,7 +1534,6 @@ void Layer::FromLayerSpecificPropertiesProto(
       ProtoToVector2dF(base.offset_to_transform_parent());
   double_sided_ = base.double_sided();
   draws_content_ = base.draws_content();
-  hide_layer_and_subtree_ = base.hide_layer_and_subtree();
   has_render_surface_ = base.has_render_surface();
   masks_to_bounds_ = base.masks_to_bounds();
   should_scroll_on_main_thread_ = base.should_scroll_on_main_thread();
@@ -1931,6 +1916,21 @@ bool Layer::HasDelegatedContent() const {
   return false;
 }
 
+bool Layer::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]

This only checks if the layer itself has an animation. It doesn't handle the
case that some ancestor has an opacity animation. For example, say we have
A->B->C, where A has an opacity animation and currently has opacity 0. In that
case, C's screen space opacity will be 0 right now, and C itself won't have an
opacity animation, but C's screen space opacity can still become non-0 during
A's opacity animation.

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

Done.

+      OpacityCanAnimateOnImplThread() || !background_filters().IsEmpty())
+    return true;
+  EffectTree& effect_tree = layer_tree_host_->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;
+}
+
 void Layer::SetFrameTimingRequests(
     const std::vector<FrameTimingRequest>& requests) {
   // TODO(vmpstr): Early out if there are no changes earlier in the call stack.