cc: Make tiling interest rect calc based on viewport.

cc/trees/layer_tree_settings.h

Index: cc/trees/layer_tree_settings.h
diff --git a/cc/trees/layer_tree_settings.h b/cc/trees/layer_tree_settings.h
index 661c7e476cd02d5d222e23bc1e704ac84cef0127..b97fbb0a8a63a5ff0e70ef329e0198925bbbfa34 100644
--- a/cc/trees/layer_tree_settings.h
+++ b/cc/trees/layer_tree_settings.h
@@ -66,7 +66,7 @@ class CC_EXPORT LayerTreeSettings {
   gfx::Size minimum_occlusion_tracking_size;
   bool use_pinch_zoom_scrollbars;
   bool use_pinch_virtual_viewport;
-  size_t max_tiles_for_interest_area;
+  float tiling_interest_area_viewport_multiplier;
   float skewport_target_time_in_seconds;
   int skewport_extrapolation_limit_in_content_pixels;
   size_t max_unused_resource_memory_percentage;