Add NativePixmapHandle type & interface for exporting them

ui/ozone/common/stub_client_native_pixmap_factory.cc

Index: ui/ozone/common/stub_client_native_pixmap_factory.cc
diff --git a/ui/ozone/common/stub_client_native_pixmap_factory.cc b/ui/ozone/common/stub_client_native_pixmap_factory.cc
index 2b74cf81cce4733f873d9f1b959494fec3d884ae..3cb944033173db268186678766573f768e35922d 100644
--- a/ui/ozone/common/stub_client_native_pixmap_factory.cc
+++ b/ui/ozone/common/stub_client_native_pixmap_factory.cc
@@ -19,12 +19,12 @@ class StubClientNativePixmapFactory : public ClientNativePixmapFactory {
   std::vector<Configuration> GetSupportedConfigurations() const override {
     return std::vector<Configuration>();
   }
-  scoped_ptr<ClientNativePixmap> ImportNativePixmap(
-      const base::FileDescriptor& handle,
+  scoped_ptr<ClientNativePixmap> ImportFromHandle(
+      const gfx::NativePixmapHandle& handle,
       const gfx::Size& size,
       gfx::BufferFormat format,
       gfx::BufferUsage usage) override {
-    NOTIMPLEMENTED();
+    NOTREACHED();
     return nullptr;
   }