ozone: Add post message loop initialization hook

ui/ozone/demo/ozone_demo.cc

Index: ui/ozone/demo/ozone_demo.cc
diff --git a/ui/ozone/demo/ozone_demo.cc b/ui/ozone/demo/ozone_demo.cc
index 616bd9ffb9b0843683892c9fd73a17f1095d7f18..321693067074d54d421915370dfbbbb782925bd9 100644
--- a/ui/ozone/demo/ozone_demo.cc
+++ b/ui/ozone/demo/ozone_demo.cc
@@ -199,13 +199,15 @@ RendererFactory::~RendererFactory() {
 bool RendererFactory::Initialize() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (!command_line->HasSwitch(kDisableGpu) &&
-      gfx::GLSurface::InitializeOneOff() &&
-      gpu_helper_.Initialize(base::ThreadTaskRunnerHandle::Get(),
-                             base::ThreadTaskRunnerHandle::Get())) {
-    if (command_line->HasSwitch(switches::kOzoneUseSurfaceless)) {
-      type_ = SURFACELESS_GL;
-    } else {
-      type_ = GL;
+      gfx::GLSurface::InitializeOneOff()) {
+    ui::OzonePlatform::InitializeForGPUPostMainLoop();
+    if (gpu_helper_.Initialize(base::ThreadTaskRunnerHandle::Get(),
+                               base::ThreadTaskRunnerHandle::Get())) {
+      if (command_line->HasSwitch(switches::kOzoneUseSurfaceless)) {
+        type_ = SURFACELESS_GL;
+      } else {
+        type_ = GL;
+      }
     }
   } else {
     type_ = SOFTWARE;