Revert of Introduce the devices Mojo app

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 300f4d69826c579bfd090273cfc67b49dc8d0a42..00fa17902ab70f58e4ea26467a45085fc227f2f1 100644
--- a/device/core/device_client.h
+++ b/device/core/device_client.h
@@ -34,6 +34,11 @@
   // Returns the UsbService instance for this embedder.
   virtual UsbService* GetUsbService();
 
+  // Connects a USB DeviceManager client to a concrete implementation. If
+  // no such implementation is available the request is dropped.
+  virtual void ConnectToUSBDeviceManager(
+      mojo::InterfaceRequest<usb::DeviceManager> request);
+
   // Returns the HidService instance for this embedder.
   virtual HidService* GetHidService();