Remove InitializeForUI() from OzonePlatform

ui/ozone/platform/x11/ozone_platform_x11.cc

Index: ui/ozone/platform/x11/ozone_platform_x11.cc
diff --git a/ui/ozone/platform/x11/ozone_platform_x11.cc b/ui/ozone/platform/x11/ozone_platform_x11.cc
index 03ac7cc92662e59bd09d6440cc84658e83e0ba6d..890e91c72c76d7b8e463cacd673f86b88755a30e 100644
--- a/ui/ozone/platform/x11/ozone_platform_x11.cc
+++ b/ui/ozone/platform/x11/ozone_platform_x11.cc
@@ -93,15 +93,11 @@ class OzonePlatformX11 : public OzonePlatform {
     gpu_platform_support_host_.reset(CreateStubGpuPlatformSupportHost());
   }
 
-  void InitializeUI() override { NOTREACHED(); }
-
   void InitializeGPU(const InitParams& params) override {
     InitializeCommon(params);
     surface_factory_ozone_.reset(new X11SurfaceFactory());
   }
 
-  void InitializeGPU() override { NOTREACHED(); }
-
   base::MessageLoop::Type GetMessageLoopTypeForGpu() override {
     // When Ozone X11 backend is running use an UI loop to grab Expose events.
     // See GLSurfaceGLX and https://crbug.com/326995.