cc: Change max_tiles_for_interest_rect to be screen pixels padding.

cc/trees/layer_tree_settings.cc

Index: cc/trees/layer_tree_settings.cc
diff --git a/cc/trees/layer_tree_settings.cc b/cc/trees/layer_tree_settings.cc
index 56720ddb5228b2d27fadbc98bec6b44dd8116797..483f86a6adf6e0c75a027bcd4ccd5397d7bbd11f 100644
--- a/cc/trees/layer_tree_settings.cc
+++ b/cc/trees/layer_tree_settings.cc
@@ -52,8 +52,8 @@ LayerTreeSettings::LayerTreeSettings()
       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),
@@ -73,8 +73,7 @@ LayerTreeSettings::LayerTreeSettings()
       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() {}