Allow native_viewport to create new native windows on demand on Android.

services/native_viewport/native_viewport_impl.cc

Index: services/native_viewport/native_viewport_impl.cc
diff --git a/services/native_viewport/native_viewport_impl.cc b/services/native_viewport/native_viewport_impl.cc
index 1fcb20f701312e71437af1a1c8bfb199877c0ec0..3d779a721ebdf116643770cc564de4198420894f 100644
--- a/services/native_viewport/native_viewport_impl.cc
+++ b/services/native_viewport/native_viewport_impl.cc
@@ -163,4 +163,12 @@ void NativeViewportImpl::AckEvent(int32 pointer_id) {
   pointers_waiting_on_ack_.erase(pointer_id);
 }
 
+base::WeakPtr<NativeViewportImpl> NativeViewportImpl::GetWeakPtr() {
+  return weak_factory_.GetWeakPtr();
+}
+
+bool NativeViewportImpl::NewNativeSurfaceAvailable() {
+  return platform_viewport_->NewNativeSurfaceAvailable();
+}
+
 }  // namespace native_viewport