aura: Add flush() to make sure delete operations make it through when we intend.

content/browser/renderer_host/image_transport_factory.cc

Index: content/browser/renderer_host/image_transport_factory.cc
diff --git a/content/browser/renderer_host/image_transport_factory.cc b/content/browser/renderer_host/image_transport_factory.cc
index 4746c5da63d651bff4f0275cd24f88b60765f03f..f7d207221c265484ed56cc4c2dfe4620c72c3cd7 100644
--- a/content/browser/renderer_host/image_transport_factory.cc
+++ b/content/browser/renderer_host/image_transport_factory.cc
@@ -299,6 +299,7 @@ class GpuProcessTransportFactory : public ui::ContextFactory,
           surface.parent_context_id == context_id) {
         data->shared_context->deleteTexture(surface.parent_texture_id[0]);
         data->shared_context->deleteTexture(surface.parent_texture_id[1]);
+        data->shared_context->flush();
         break;
       }
     }