Defer compositor context creation to the thread.

cc/surfaces/surface_display_output_surface_unittest.cc

Index: cc/surfaces/surface_display_output_surface_unittest.cc
diff --git a/cc/surfaces/surface_display_output_surface_unittest.cc b/cc/surfaces/surface_display_output_surface_unittest.cc
index f263363bd14bb735db2bf549232146541e4483af..f1731db59368329e9dabfe84d6fc32a7781d6631 100644
--- a/cc/surfaces/surface_display_output_surface_unittest.cc
+++ b/cc/surfaces/surface_display_output_surface_unittest.cc
@@ -63,11 +63,11 @@ class SurfaceDisplayOutputSurfaceTest : public testing::Test {
                         renderer_settings_,
                         task_runner_,
                         allocator_.id_namespace()),
-        context_provider_(TestContextProvider::Create()),
-        surface_display_output_surface_(&surface_manager_,
-                                        &allocator_,
-                                        context_provider_,
-                                        nullptr) {
+        surface_display_output_surface_(
+            &surface_manager_,
+            &allocator_,
+            base::MakeUnique<TestContextProvider::Factory>(),
+            nullptr) {
     surface_manager_.RegisterSurfaceIdNamespace(allocator_.id_namespace());
     output_surface_ = display_client_.output_surface();
     display_client_.set_surface_output_surface(
@@ -129,8 +129,6 @@ class SurfaceDisplayOutputSurfaceTest : public testing::Test {
   RendererSettings renderer_settings_;
   FakeOnscreenDisplayClient display_client_;
 
-  scoped_refptr<TestContextProvider> context_provider_;
-
   FakeOutputSurfaceClient surface_display_output_surface_client_;
   SurfaceDisplayOutputSurface surface_display_output_surface_;
 };