Add flag to enable rendering of text using signed distance fields.

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 22aa83f96e64475358e493e1d47af6b193513b28..f11f2cac958b3c4ded5cd6fac53ddbb8cad396a8 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -1931,7 +1931,8 @@ bool LayerTreeHostImpl::InitializeRenderer(
                                shared_bitmap_manager_,
                                settings_.highp_threshold_min,
                                settings_.use_rgba_4444_textures,
-                               settings_.texture_id_allocation_chunk_size);
+                               settings_.texture_id_allocation_chunk_size,
+                               settings_.use_distance_field_text);
 
   if (output_surface->capabilities().deferred_gl_initialization)
     EnforceZeroBudget(true);