Use StrongBinding in NativeViewportImpl instead of manually deleting-on-connection-error.

components/view_manager/native_viewport/native_viewport_impl.cc

Index: components/view_manager/native_viewport/native_viewport_impl.cc
diff --git a/components/view_manager/native_viewport/native_viewport_impl.cc b/components/view_manager/native_viewport/native_viewport_impl.cc
index 5c623940206a114d0a7acdcfea38cbc53366dc41..e990cbdcc71414a76140ca028d4db58091af4ca7 100644
--- a/components/view_manager/native_viewport/native_viewport_impl.cc
+++ b/components/view_manager/native_viewport/native_viewport_impl.cc
@@ -29,7 +29,6 @@ NativeViewportImpl::NativeViewportImpl(
       metrics_(mojo::ViewportMetrics::New()),
       binding_(this, request.Pass()),
       weak_factory_(this) {
-  binding_.set_error_handler(this);
 }
 
 NativeViewportImpl::~NativeViewportImpl() {
@@ -160,11 +159,6 @@ void NativeViewportImpl::OnDestroyed() {
   delete this;
 }
 
-void NativeViewportImpl::OnConnectionError() {
-  binding_.set_error_handler(nullptr);
-  delete this;
-}
-
 void NativeViewportImpl::AckEvent(int32 pointer_id) {
   pointers_waiting_on_ack_.erase(pointer_id);
 }