cc : Delete LayerImpl::OnOpacityAnimated

cc/input/scrollbar_animation_controller_linear_fade.cc

Index: cc/input/scrollbar_animation_controller_linear_fade.cc
diff --git a/cc/input/scrollbar_animation_controller_linear_fade.cc b/cc/input/scrollbar_animation_controller_linear_fade.cc
index 8ead32491a3f9eebd4ccc55b1bdb3f77ab04cf89..8695bfaf6cf57b4199e3faec1a4ae539f50a0795 100644
--- a/cc/input/scrollbar_animation_controller_linear_fade.cc
+++ b/cc/input/scrollbar_animation_controller_linear_fade.cc
@@ -8,6 +8,7 @@
 #include "base/time/time.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/scrollbar_layer_impl_base.h"
+#include "cc/trees/layer_tree_impl.h"
 
 namespace cc {
 
@@ -55,8 +56,20 @@ void ScrollbarAnimationControllerLinearFade::ApplyOpacityToScrollbars(
   for (ScrollbarLayerImplBase* scrollbar : Scrollbars()) {
     if (!scrollbar->is_overlay_scrollbar())
       continue;
-    scrollbar->OnOpacityAnimated(scrollbar->CanScrollOrientation() ? opacity
-                                                                   : 0);
+    PropertyTrees* property_trees =
+        scrollbar->layer_tree_impl()->property_trees();
+    // If this method is called during LayerImpl::PushPropertiesTo, we may not
+    // yet have valid effect_id_to_index_map entries as property trees are
+    // pushed after layers during activation. We can skip updating opacity in
+    // that case as we are only registering a scrollbar and because opacity will
+    // be overwritten anyway when property trees are pushed.
+    if (property_trees->IsInIdToIndexMap(PropertyTrees::TreeType::EFFECT,
+                                         scrollbar->id())) {
+      property_trees->effect_tree.OnOpacityAnimated(
+          scrollbar->CanScrollOrientation() ? opacity : 0,
+          property_trees->effect_id_to_index_map[scrollbar->id()],
+          scrollbar->layer_tree_impl());
+    }
   }
 }