Always create ClientNativePixmapFactory in chrome --mash

ui/gfx/client_native_pixmap_factory.cc

Index: ui/gfx/client_native_pixmap_factory.cc
diff --git a/ui/gfx/client_native_pixmap_factory.cc b/ui/gfx/client_native_pixmap_factory.cc
index 37d3306c887e117392e4168c91bf952d26d98948..f88b4fdeef3bbaa724d67d217a15dbc6f5e7051f 100644
--- a/ui/gfx/client_native_pixmap_factory.cc
+++ b/ui/gfx/client_native_pixmap_factory.cc
@@ -18,6 +18,11 @@ ClientNativePixmapFactory* ClientNativePixmapFactory::GetInstance() {
 }
 
 // static
+void ClientNativePixmapFactory::ResetInstance() {
+  g_instance = nullptr;
+}
+
+// static
 void ClientNativePixmapFactory::SetInstance(
     ClientNativePixmapFactory* instance) {
   DCHECK(!g_instance);