stop using SkXfermode -- use SkBlendMode instead

cc/layers/layer_impl.cc

 // Copyright 2012 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/layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 52 matching lines @@
       masks_to_bounds_(false),
       contents_opaque_(false),
       use_parent_backface_visibility_(false),
       use_local_transform_for_backface_visibility_(false),
       should_check_backface_visibility_(false),
       draws_content_(false),
       is_drawn_render_surface_layer_list_member_(false),
       was_ever_ready_since_last_transform_animation_(true),
       background_color_(0),
       safe_opaque_background_color_(0),
-      draw_blend_mode_(SkXfermode::kSrcOver_Mode),
+      draw_blend_mode_(SkBlendMode::kSrcOver),
       transform_tree_index_(TransformTree::kInvalidNodeId),
       effect_tree_index_(EffectTree::kInvalidNodeId),
       clip_tree_index_(ClipTree::kInvalidNodeId),
       scroll_tree_index_(ScrollTree::kInvalidNodeId),
       sorting_context_id_(0),
       current_draw_mode_(DRAW_MODE_NONE),
       mutable_properties_(MutableProperty::kNone),
       debug_info_(nullptr),
       has_preferred_raster_bounds_(false),
       has_will_change_transform_hint_(false),
@@ skipping 1015 matching lines @@
            .layer_transforms_should_scale_layer_contents) {
     return default_scale;
   }
 
   gfx::Vector2dF transform_scales = MathUtil::ComputeTransform2dScaleComponents(
       ScreenSpaceTransform(), default_scale);
   return std::max(transform_scales.x(), transform_scales.y());
 }
 
 }  // namespace cc