Refactor GvrDelegate ownership into GvrDelegateProvider and fix more threading violations.

device/vr/vr_device.h

Index: device/vr/vr_device.h
diff --git a/device/vr/vr_device.h b/device/vr/vr_device.h
index d2ed8fa8dcebb27a547b58c819e05b9b38f6dad5..be836ee12016272cdbcb11abc704cd63380d2396 100644
--- a/device/vr/vr_device.h
+++ b/device/vr/vr_device.h
@@ -23,7 +23,8 @@ class DEVICE_VR_EXPORT VRDevice {
 
   unsigned int id() const { return id_; }
 
-  virtual mojom::VRDisplayInfoPtr GetVRDevice() = 0;
+  virtual void GetVRDevice(
+      const base::Callback<void(mojom::VRDisplayInfoPtr)>& callback) = 0;
   virtual void ResetPose() = 0;
 
   virtual void RequestPresent(const base::Callback<void(bool)>& callback) = 0;
@@ -55,6 +56,8 @@ class DEVICE_VR_EXPORT VRDevice {
   void SetPresentingDisplay(VRDisplayImpl* display);
 
  private:
+  void OnVRDisplayInfoCreated(mojom::VRDisplayInfoPtr vr_device_info);
+
   std::set<VRDisplayImpl*> displays_;
 
   VRDisplayImpl* presenting_display_;
@@ -63,6 +66,8 @@ class DEVICE_VR_EXPORT VRDevice {
 
   static unsigned int next_id_;
 
+  base::WeakPtrFactory<VRDevice> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(VRDevice);
 };