cc: Separate raster and decode prepaint regions.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index c69ae07733511c79a89575390c6541a079aaebe9..df01a22383b74000629965c9a2bfe8a97ab8d821 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -218,12 +218,14 @@ LayerTreeHostImpl::LayerTreeHostImpl(
       // TODO(vmpstr): TileManager takes a scoped reftr for the task runner,
       // figure out if it actually needs a ref or whether it can use a raw
       // pointer.
-      tile_manager_(new TileManager(this,
-                                    GetTaskRunner(),
-                                    is_synchronous_single_threaded_
-                                        ? std::numeric_limits<size_t>::max()
-                                        : settings.scheduled_raster_task_limit,
-                                    settings.use_partial_raster)),
+      tile_manager_(
+          new TileManager(this,
+                          GetTaskRunner(),
+                          is_synchronous_single_threaded_
+                              ? std::numeric_limits<size_t>::max()
+                              : settings.scheduled_raster_task_limit,
+                          settings.use_partial_raster,
+                          settings.max_preraster_distance_in_screen_pixels)),
       pinch_gesture_active_(false),
       pinch_gesture_end_should_clear_scrolling_layer_(false),
       fps_counter_(