Teach the native viewport service to draw a Surface into itself

mojo/services/native_viewport/BUILD.gn

Index: mojo/services/native_viewport/BUILD.gn
diff --git a/mojo/services/native_viewport/BUILD.gn b/mojo/services/native_viewport/BUILD.gn
index 794915616378896423018fd3d0eb6c070447e353..34ec95f8ee8f9f1a52c4b7214a982c71f40f13ec 100644
--- a/mojo/services/native_viewport/BUILD.gn
+++ b/mojo/services/native_viewport/BUILD.gn
@@ -10,18 +10,21 @@ static_library("native_viewport") {
 
   deps = [
     "//base",
-    "//ui/events",
-    "//ui/events/platform",
-    "//ui/gfx",
-    "//ui/gfx/geometry",
-    "//mojo/public/cpp/application:chromium",
+    "//cc/surfaces",
     "//mojo/common",
     "//mojo/environment:chromium",
-    "//mojo/services/public/cpp/geometry",
-    "//mojo/services/public/interfaces/geometry",
+    "//mojo/public/cpp/application:chromium",
     "//mojo/services/gles2",
+    "//mojo/services/public/cpp/geometry",
     "//mojo/services/public/cpp/input_events",
+    "//mojo/services/public/cpp/surfaces",
+    "//mojo/services/public/interfaces/geometry",
     "//mojo/services/public/interfaces/native_viewport",
+    "//mojo/services/public/interfaces/surfaces",
+    "//ui/events",
+    "//ui/events/platform",
+    "//ui/gfx",
+    "//ui/gfx/geometry",
   ]
 
   sources = [
@@ -34,6 +37,8 @@ static_library("native_viewport") {
     "platform_viewport_android.h",
     "platform_viewport_mac.mm",
     "platform_viewport_win.cc",
+    "viewport_surface.cc",
+    "viewport_surface.h",
   ]
 
   if (is_ios) {