cc: Stop creating unused 0 property tree nodes other than transform

cc/layers/render_surface_impl.cc

 // Copyright 2011 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 "cc/layers/render_surface_impl.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 27 matching lines @@
   damage_tracker_ = DamageTracker::Create();
 }
 
 RenderSurfaceImpl::~RenderSurfaceImpl() {}
 
 RenderSurfaceImpl* RenderSurfaceImpl::render_target() {
   EffectTree& effect_tree =
       owning_layer_->layer_tree_impl()->property_trees()->effect_tree;
   EffectNode* node = effect_tree.Node(EffectTreeIndex());
   EffectNode* target_node = effect_tree.Node(node->data.target_id);
-  if (target_node->id != 0)
-    return target_node->data.render_surface;
-  else
-    return this;
+  return target_node->data.render_surface;
 }
 
 const RenderSurfaceImpl* RenderSurfaceImpl::render_target() const {
   const EffectTree& effect_tree =
       owning_layer_->layer_tree_impl()->property_trees()->effect_tree;
   const EffectNode* node = effect_tree.Node(EffectTreeIndex());
   const EffectNode* target_node = effect_tree.Node(node->data.target_id);
-  if (target_node->id != 0)
-    return target_node->data.render_surface;
-  else
-    return this;
+  return target_node->data.render_surface;
 }
 
 RenderSurfaceImpl::DrawProperties::DrawProperties() {
   draw_opacity = 1.f;
   is_clipped = false;
 }
 
 RenderSurfaceImpl::DrawProperties::~DrawProperties() {}
 
 gfx::RectF RenderSurfaceImpl::DrawableContentRect() const {
@@ skipping 316 matching lines @@
   RenderPassDrawQuad* quad =
       render_pass->CreateAndAppendDrawQuad<RenderPassDrawQuad>();
   quad->SetNew(shared_quad_state, content_rect(), visible_layer_rect,
                render_pass_id, mask_resource_id, mask_uv_scale,
                mask_texture_size, owning_layer_->filters(),
                owning_layer_to_target_scale,
                owning_layer_->background_filters());
 }
 
 }  // namespace cc