Refactor GvrDelegate ownership into GvrDelegateProvider and fix more threading violations.

device/vr/vr_display_impl.h

Index: device/vr/vr_display_impl.h
diff --git a/device/vr/vr_display_impl.h b/device/vr/vr_display_impl.h
index 02a1e1a17c9f2022f6ed1ea416fb09910b6a8e68..7116d520d1ad314bf74976376696bcbaec2824b2 100644
--- a/device/vr/vr_display_impl.h
+++ b/device/vr/vr_display_impl.h
@@ -45,6 +45,8 @@ class VRDisplayImpl : public mojom::VRDisplay {
                             bool secure_origin,
                             bool success);
 
+  void OnVRDisplayInfoCreated(mojom::VRDisplayInfoPtr display_info);
+
   mojo::Binding<mojom::VRDisplay> binding_;
   mojom::VRDisplayClientPtr client_;
   device::VRDevice* device_;