Fix ws::Display initialization order.

services/ui/ws/platform_display.cc

Index: services/ui/ws/platform_display.cc
diff --git a/services/ui/ws/platform_display.cc b/services/ui/ws/platform_display.cc
index a490ff4ee70541f9f37ea7b5c343fb753c564705..e1f799c7841029610b44a1f3ecd8299f421ed5c1 100644
--- a/services/ui/ws/platform_display.cc
+++ b/services/ui/ws/platform_display.cc
@@ -4,6 +4,8 @@
 
 #include "services/ui/ws/platform_display.h"
 
+#include <utility>
+
 #include "base/numerics/safe_conversions.h"
 #include "build/build_config.h"
 #include "cc/ipc/quads.mojom.h"
@@ -43,12 +45,12 @@ namespace ws {
 PlatformDisplayFactory* PlatformDisplay::factory_ = nullptr;
 
 // static
-PlatformDisplay* PlatformDisplay::Create(
+std::unique_ptr<PlatformDisplay> PlatformDisplay::Create(
     const PlatformDisplayInitParams& init_params) {
   if (factory_)
     return factory_->CreatePlatformDisplay();
 
-  return new DefaultPlatformDisplay(init_params);
+  return base::MakeUnique<DefaultPlatformDisplay>(init_params);
 }
 
 DefaultPlatformDisplay::DefaultPlatformDisplay(
@@ -256,6 +258,10 @@ void DefaultPlatformDisplay::OnLostCapture() {
 void DefaultPlatformDisplay::OnAcceleratedWidgetAvailable(
     gfx::AcceleratedWidget widget,
     float device_scale_factor) {
+  // This will get called after Init() is called, either synchronously as part
+  // of the Init() callstack or async after Init() has returned, depending on
+  // the platform.
+  delegate_->OnAcceleratedWidgetAvailable();
   frame_generator_->OnAcceleratedWidgetAvailable(widget);
 }