Use a cc::Display for layout tests.

cc/trees/proxy_impl.cc

Index: cc/trees/proxy_impl.cc
diff --git a/cc/trees/proxy_impl.cc b/cc/trees/proxy_impl.cc
index 7eb134801d372af580fccdd06474d26501f8fd44..0d7e4eee11ebce067fa9468ecb944b1dbde05b4f 100644
--- a/cc/trees/proxy_impl.cc
+++ b/cc/trees/proxy_impl.cc
@@ -115,6 +115,10 @@ ProxyImpl::~ProxyImpl() {
   DCHECK(IsImplThread());
   DCHECK(IsMainThreadBlocked());
 
+  // Take away the OutputSurface before destroying things so it doesn't try
+  // to call into its client mid-shutdown.
+  layer_tree_host_impl_->ReleaseOutputSurface();
+
   scheduler_ = nullptr;
   external_begin_frame_source_ = nullptr;
   unthrottled_begin_frame_source_ = nullptr;