Provide WebVR pose data only to the focused frame.

third_party/WebKit/Source/modules/vr/VRController.h

Index: third_party/WebKit/Source/modules/vr/VRController.h
diff --git a/third_party/WebKit/Source/modules/vr/VRController.h b/third_party/WebKit/Source/modules/vr/VRController.h
index ee0c6fcdd15652224694d6bb84beeb24420f8390..18ca8eb2598e0ee9238a82ee0a07b9529c330e4d 100644
--- a/third_party/WebKit/Source/modules/vr/VRController.h
+++ b/third_party/WebKit/Source/modules/vr/VRController.h
@@ -38,6 +38,8 @@ class VRController final : public GarbageCollectedFinalized<VRController>,
                           device::mojom::blink::VRDisplayClientRequest,
                           device::mojom::blink::VRDisplayInfoPtr) override;
 
+  void focusChanged(bool focused);
+
   DECLARE_VIRTUAL_TRACE();
 
  private:
@@ -52,6 +54,7 @@ class VRController final : public GarbageCollectedFinalized<VRController>,
   VRDisplayVector m_displays;
 
   bool m_displaySynced;
+  bool m_focused = false;
   unsigned m_numberOfSyncedDisplays;
 
   Deque<std::unique_ptr<VRGetDevicesCallback>> m_pendingGetDevicesCallbacks;