Remove enable/disable wheel gestures setting.

cc/trees/layer_tree_settings.h

 // 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.
 
 #ifndef CC_TREES_LAYER_TREE_SETTINGS_H_
 #define CC_TREES_LAYER_TREE_SETTINGS_H_
 
 #include <stddef.h>
 
 #include <vector>
@@ skipping 76 matching lines @@
   bool enable_elastic_overscroll = false;
   // An array of image texture targets for each GpuMemoryBuffer format.
   std::vector<unsigned> use_image_texture_targets;
   bool ignore_root_layer_flings = false;
   size_t scheduled_raster_task_limit = 32;
   bool use_occlusion_for_tile_prioritization = false;
   bool verify_clip_tree_calculations = false;
   bool image_decode_tasks_enabled = false;
   bool wait_for_beginframe_interval = true;
   bool abort_commit_before_output_surface_creation = true;
-  bool use_mouse_wheel_gestures = false;
   bool use_layer_lists = false;
   int max_staging_buffer_usage_in_bytes = 32 * 1024 * 1024;
   ManagedMemoryPolicy memory_policy_;
   size_t gpu_decoded_image_budget_bytes = 96 * 1024 * 1024;
   size_t software_decoded_image_budget_bytes = 128 * 1024 * 1024;
   int max_preraster_distance_in_screen_pixels = 1000;
 
   // If set to true, the display item list will internally cache a SkPicture for
   // raster rather than directly using the display items.
   bool use_cached_picture_raster = true;
 
   LayerTreeDebugState initial_debug_state;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_SETTINGS_H_