Fix HidService lifetime issues

device/core/device_client.h

Index: device/core/device_client.h
diff --git a/device/core/device_client.h b/device/core/device_client.h
index 3ca3130c0ad455412a170cfa598230f3039397d5..b4a9934e55b12774b8cb1c7dc5ef0016a2ef7582 100644
--- a/device/core/device_client.h
+++ b/device/core/device_client.h
@@ -9,6 +9,7 @@
 
 namespace device {
 
+class HidService;
 class UsbService;
 
 // Interface used by consumers of //device APIs to get pointers to the service
@@ -28,6 +29,9 @@ class DeviceClient {
   // Returns the UsbService instance for this embedder.
   virtual UsbService* GetUsbService();
 
+  // Returns the HidService instance for this embedder.
+  virtual HidService* GetHidService();
+
  private:
   DISALLOW_COPY_AND_ASSIGN(DeviceClient);
 };