cc: Enable composited border-radius scrolling.

cc/layers/render_surface_impl.cc

Index: cc/layers/render_surface_impl.cc
diff --git a/cc/layers/render_surface_impl.cc b/cc/layers/render_surface_impl.cc
index eba8543beccce7560c21c79ecb772ad3d5282bcd..29294447415a7cec5d28bd36023cf3366b1dfb2f 100644
--- a/cc/layers/render_surface_impl.cc
+++ b/cc/layers/render_surface_impl.cc
@@ -406,6 +406,9 @@ void RenderSurfaceImpl::AppendQuads(RenderPass* render_pass,
     // mask layers.
     DCHECK(BlendMode() != SkBlendMode::kDstIn)
         << "kDstIn blend mode with mask layer is unsupported.";
+    TRACE_EVENT1("cc", "RenderSurfaceImpl::AppendQuads",
+                 "mask_layer_gpu_memory_usage",
+                 mask_layer->GPUMemoryUsageInBytes());
     if (mask_layer->mask_type() == Layer::LayerMaskType::MULTI_TEXTURE_MASK) {
       TileMaskLayer(render_pass, shared_quad_state, visible_layer_rect);
       return;