cc: Change max_tiles_for_interest_rect to be screen pixels padding.

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 <limits>
 
 #include "base/command_line.h"
@@ skipping 34 matching lines @@
       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),
       max_partial_texture_updates(std::numeric_limits<size_t>::max()),
       default_tile_size(gfx::Size(256, 256)),
       max_untiled_layer_size(gfx::Size(512, 512)),
       default_tile_grid_size(gfx::Size(256, 256)),
       minimum_occlusion_tracking_size(gfx::Size(160, 160)),
-      // At 256x256 tiles, 128 tiles cover an area of 2048x4096 pixels.
-      max_tiles_for_interest_area(128),
+      // 3000 pixels should give sufficient area for prepainting.
+      tiling_interest_area_padding(3000),
       skewport_target_time_in_seconds(1.0f),
       skewport_extrapolation_limit_in_content_pixels(2000),
       max_unused_resource_memory_percentage(100),
       max_memory_for_prepaint_percentage(100),
       strict_layer_property_change_checking(false),
       use_one_copy(true),
       use_zero_copy(false),
       use_persistent_map_for_gpu_memory_buffers(false),
       enable_elastic_overscroll(false),
       use_image_texture_target(GL_TEXTURE_2D),
       ignore_root_layer_flings(false),
       scheduled_raster_task_limit(32),
       use_occlusion_for_tile_prioritization(false),
       record_full_layer(false),
       use_display_lists(false),
       verify_property_trees(false),
       gather_pixel_refs(false),
       use_compositor_animation_timelines(false),
       invert_viewport_scroll_order(false),
-      wait_for_beginframe_interval(true) {
-}
+      wait_for_beginframe_interval(true) {}
 
 LayerTreeSettings::~LayerTreeSettings() {}
 
 SchedulerSettings LayerTreeSettings::ToSchedulerSettings() const {
   SchedulerSettings scheduler_settings;
   scheduler_settings.use_external_begin_frame_source =
       use_external_begin_frame_source;
   scheduler_settings.main_frame_before_activation_enabled =
       main_frame_before_activation_enabled;
   scheduler_settings.timeout_and_draw_when_animation_checkerboards =
       timeout_and_draw_when_animation_checkerboards;
   scheduler_settings.using_synchronous_renderer_compositor =
       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);
   return scheduler_settings;
 }
 
 }  // namespace cc