Update cc effect node documentation.

cc/trees/effect_node.cc

 // Copyright 2016 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 "base/trace_event/trace_event_argument.h"
 #include "cc/layers/layer.h"
 #include "cc/trees/effect_node.h"
 #include "cc/trees/property_tree.h"
 
 namespace cc {
 
 EffectNode::EffectNode()
     : id(EffectTree::kInvalidNodeId),
       parent_id(EffectTree::kInvalidNodeId),
       owning_layer_id(Layer::INVALID_ID),
       opacity(1.f),
       screen_space_opacity(1.f),
       blend_mode(SkBlendMode::kSrcOver),
       has_render_surface(false),
       has_copy_request(false),
       hidden_by_backface_visibility(false),
       double_sided(false),
       is_drawn(true),
       subtree_hidden(false),
       has_potential_filter_animation(false),
       has_potential_opacity_animation(false),
       is_currently_animating_filter(false),
       is_currently_animating_opacity(false),
       effect_changed(false),
-      subtree_has_copy_request(0),
+      subtree_has_copy_request(false),
       transform_id(0),
       clip_id(0),
       target_id(1),
-      mask_layer_id(-1),
+      mask_layer_id(Layer::INVALID_ID),
       closest_ancestor_with_copy_request_id(-1) {}
 
 EffectNode::EffectNode(const EffectNode& other) = default;
 
 bool EffectNode::operator==(const EffectNode& other) const {
   return id == other.id && parent_id == other.parent_id &&
          owning_layer_id == other.owning_layer_id && opacity == other.opacity &&
          screen_space_opacity == other.screen_space_opacity &&
          has_render_surface == other.has_render_surface &&
          has_copy_request == other.has_copy_request &&
@@ skipping 38 matching lines @@
   value->SetInteger("subtree_has_copy_request", subtree_has_copy_request);
   value->SetInteger("transform_id", transform_id);
   value->SetInteger("clip_id", clip_id);
   value->SetInteger("target_id", target_id);
   value->SetInteger("mask_layer_id", mask_layer_id);
   value->SetInteger("closest_ancestor_with_copy_request_id",
                     closest_ancestor_with_copy_request_id);
 }
 
 }  // namespace cc