Revert of Introduce the devices Mojo app

device/core/device_client.cc

Index: device/core/device_client.cc
diff --git a/device/core/device_client.cc b/device/core/device_client.cc
index 52021221d9f0fc84130109ba6846a7d3eafd0627..2aca21693a2d597898b8565dccd4a2506dc2ff3f 100644
--- a/device/core/device_client.cc
+++ b/device/core/device_client.cc
@@ -35,6 +35,10 @@
   return NULL;
 }
 
+void DeviceClient::ConnectToUSBDeviceManager(
+    mojo::InterfaceRequest<usb::DeviceManager> request) {
+}
+
 HidService* DeviceClient::GetHidService() {
   // This should never be called by clients which do not support the HID API.
   NOTREACHED();