cc: Make LayerTreeTests use a DelegatingRenderer and Display.

services/ui/surfaces/display_compositor.cc

Index: services/ui/surfaces/display_compositor.cc
diff --git a/services/ui/surfaces/display_compositor.cc b/services/ui/surfaces/display_compositor.cc
index 1f38c4f88c6a5ea8f1dff4bf31bdc86da51b3db0..5cb51a19d13c6a272473408d3871c82933739c21 100644
--- a/services/ui/surfaces/display_compositor.cc
+++ b/services/ui/surfaces/display_compositor.cc
@@ -121,4 +121,16 @@ void DisplayCompositor::DisplayOutputSurfaceLost() {
 void DisplayCompositor::DisplaySetMemoryPolicy(
     const cc::ManagedMemoryPolicy& policy) {}
 
+void DisplayCompositor::DisplayWillDrawAndSwap(
+    bool will_draw_and_swap,
+    const cc::RenderPassList& render_passes) {
+  // This notification is not relevant to our client outside of tests.
+}
+
+void DisplayCompositor::DisplayDidDrawAndSwap() {
+  // This notification is not relevant to our client outside of tests. We
+  // unblock the client from the DrawCallback when the surface is going to
+  // be drawn.
+}
+
 }  // namespace ui