cc: Restore the space of interest area padding to be ideal contents space.

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 <GLES2/gl2.h>
 #include <stddef.h>
 #include <limits>
 
@@ skipping 67 matching lines @@
       layers_always_allowed_lcd_text(false),
       minimum_contents_scale(0.0625f),
       low_res_contents_scale_factor(0.25f),
       top_controls_show_threshold(0.5f),
       top_controls_hide_threshold(0.5f),
       background_animation_rate(1.0),
       default_tile_size(gfx::Size(256, 256)),
       max_untiled_layer_size(gfx::Size(512, 512)),
       minimum_occlusion_tracking_size(gfx::Size(160, 160)),
       // 3000 pixels should give sufficient area for prepainting.
+      // Note this value is specified with an ideal contents scale in mind. That
+      // is, the ideal tiling would use this value as the padding.
+      // TODO(vmpstr): Figure out a better number that doesn't depend on scale.
       tiling_interest_area_padding(3000),
       skewport_target_time_in_seconds(1.0f),
       skewport_extrapolation_limit_in_screen_pixels(2000),
       max_memory_for_prepaint_percentage(100),
       use_zero_copy(false),
       use_partial_raster(false),
       enable_elastic_overscroll(false),
       use_image_texture_targets(
           static_cast<size_t>(gfx::BufferFormat::LAST) + 1,
           GL_TEXTURE_2D),
@@ skipping 220 matching lines @@
       using_synchronous_renderer_compositor;
   scheduler_settings.throttle_frame_production = wait_for_beginframe_interval;
   scheduler_settings.background_frame_interval =
       base::TimeDelta::FromSecondsD(1.0 / background_animation_rate);
   scheduler_settings.abort_commit_before_output_surface_creation =
       abort_commit_before_output_surface_creation;
   return scheduler_settings;
 }
 
 }  // namespace cc