Update clang, re-enable checker, fix issues it flags

services/native_viewport/native_viewport_impl.h

Index: services/native_viewport/native_viewport_impl.h
diff --git a/services/native_viewport/native_viewport_impl.h b/services/native_viewport/native_viewport_impl.h
index 741b95ccd9dcf7a8fb46e40721ca41c30935d43c..4ac9bbd02138e312587ca9cd942448d46a9ee8fc 100644
--- a/services/native_viewport/native_viewport_impl.h
+++ b/services/native_viewport/native_viewport_impl.h
@@ -76,11 +76,12 @@ class NativeViewportImpl : public mojo::NativeViewport,
   RequestMetricsCallback metrics_callback_;
   mojo::NativeViewportEventDispatcherPtr event_dispatcher_;
   mojo::Binding<mojo::NativeViewport> binding_;
-  base::WeakPtrFactory<NativeViewportImpl> weak_factory_;
 
   // Set of pointer_ids we've sent a move to and are waiting on an ack.
   std::set<int32> pointers_waiting_on_ack_;
 
+  base::WeakPtrFactory<NativeViewportImpl> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(NativeViewportImpl);
 };