cc : Move screen space scale factor to root transform node

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/proto/gfx_conversions.h"
 #include "cc/proto/property_tree.pb.h"
 #include "cc/proto/skia_conversions.h"
 #include "cc/trees/effect_node.h"
 
@@ skipping 15 matching lines @@
       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),
       num_copy_requests_in_subtree(0),
       has_unclipped_descendants(false),
       transform_id(0),
       clip_id(0),
-      target_id(0),
+      target_id(1),
       mask_layer_id(-1) {}
 
 EffectNode::EffectNode(const EffectNode& other) = default;
 
 bool EffectNode::operator==(const EffectNode& other) const {
   return id == other.id && parent_id == other.parent_id &&
          owner_id == other.owner_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 98 matching lines @@
   value->SetBoolean("effect_changed", effect_changed);
   value->SetInteger("num_copy_requests_in_subtree",
                     num_copy_requests_in_subtree);
   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);
 }
 
 }  // namespace cc