Take 2 at removing thumb thickness compositor setting.

cc/trees/layer_tree_settings.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/trees/layer_tree_settings.h"
 
 #include <limits>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 13 matching lines @@
       accelerated_animation_enabled(true),
       background_color_instead_of_checkerboard(false),
       show_overdraw_in_tracing(false),
       can_use_lcd_text(true),
       should_clear_root_render_pass(true),
       scrollbar_animator(NoAnimator),
       scrollbar_linear_fade_delay_ms(300),
       scrollbar_linear_fade_length_ms(300),
       solid_color_scrollbars(false),
       solid_color_scrollbar_color(SK_ColorWHITE),
-      solid_color_scrollbar_thickness_dip(-1),
       calculate_top_controls_position(false),
       use_memory_management(true),
       timeout_and_draw_when_animation_checkerboards(true),
       maximum_number_of_failed_draws_before_draw_is_forced_(3),
       layer_transforms_should_scale_layer_contents(false),
       minimum_contents_scale(0.0625f),
       low_res_contents_scale_factor(0.125f),
       top_controls_height(0.f),
       top_controls_show_threshold(0.5f),
       top_controls_hide_threshold(0.5f),
@@ skipping 14 matching lines @@
       use_map_image(false),
       ignore_root_layer_flings(false) {
   // TODO(danakj): Renable surface caching when we can do it more realiably.
   // crbug.com/170713
   cache_render_pass_contents = false;
 }
 
 LayerTreeSettings::~LayerTreeSettings() {}
 
 }  // namespace cc