Open HID connections asynchronously.

device/hid/hid_service_win.h

Index: device/hid/hid_service_win.h
diff --git a/device/hid/hid_service_win.h b/device/hid/hid_service_win.h
index 4c9dec6902f285d83404082bfa6aec84a8d5214b..e9ac9e98c670c1780bbc0e6cb1ed964772c80ff8 100644
--- a/device/hid/hid_service_win.h
+++ b/device/hid/hid_service_win.h
@@ -32,8 +32,8 @@ class HidServiceWin : public HidService {
 
   virtual void GetDevices(std::vector<HidDeviceInfo>* devices) override;
 
-  virtual scoped_refptr<HidConnection> Connect(const HidDeviceId& device_id)
-      override;
+  virtual void Connect(const HidDeviceId& device_id,
+                       const ConnectCallback& callback) override;
 
  private:
   virtual ~HidServiceWin();
@@ -50,6 +50,8 @@ class HidServiceWin : public HidService {
   void PlatformAddDevice(const std::string& device_path);
   void PlatformRemoveDevice(const std::string& device_path);
 
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
   DISALLOW_COPY_AND_ASSIGN(HidServiceWin);
 };