cc: Move background filters to the effect tree

cc/proto/property_tree.proto

 // Copyright 2015 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.
 
 syntax = "proto2";
 
 import "rectf.proto";
 import "scroll_offset.proto";
 import "size.proto";
 import "synced_property.proto";
@@ skipping 77 matching lines @@
   optional bool resets_clip = 11;
 }
 
 // Proto for struct EffectNodeData.
 // NEXT ID: 20
 message EffectNodeData {
   optional float opacity = 1;
   optional float screen_space_opacity = 2;
   optional bool has_render_surface = 3;
   optional bool has_copy_request = 4;
-  optional bool has_background_filters = 5;
   optional bool hidden_by_backface_visibility = 14;
   optional bool double_sided = 13;
   optional bool is_drawn = 6;
   optional bool subtree_hidden = 15;
   optional bool has_potential_opacity_animation = 7;
   optional bool is_currently_animating_opacity = 16;
   optional bool effect_changed = 11;
   optional int64 num_copy_requests_in_subtree = 8;
   optional int64 transform_id = 9;
   optional int64 clip_id = 10;
@@ skipping 106 matching lines @@
   optional bool full_tree_damaged = 12;
   optional int64 sequence_number = 6;
   optional bool is_main_thread = 13;
   optional bool is_active = 14;
 
   optional Vector2dF inner_viewport_container_bounds_delta = 8;
   optional Vector2dF outer_viewport_container_bounds_delta = 9;
   optional Vector2dF inner_viewport_scroll_bounds_delta = 10;
   repeated int64 always_use_active_tree_opacity_effect_ids = 15 [packed = true];
 }