Clean up HID backend and API.

device/hid/hid_connection.cc

Index: device/hid/hid_connection.cc
diff --git a/device/hid/hid_connection.cc b/device/hid/hid_connection.cc
index 56784078e4e789bfc4d8946417dd691e576be7c2..c134bf2702e96aca40ca0cc58b376d9b151a1aa2 100644
--- a/device/hid/hid_connection.cc
+++ b/device/hid/hid_connection.cc
@@ -6,13 +6,17 @@
 
 namespace device {
 
-HidConnection::HidConnection(HidDeviceInfo device_info)
+PendingHidReport::PendingHidReport() {}
+
+PendingHidReport::~PendingHidReport() {}
+
+PendingHidRead::PendingHidRead() {}
+
+PendingHidRead::~PendingHidRead() {}
+
+HidConnection::HidConnection(const HidDeviceInfo& device_info)
     : device_info_(device_info) {}
 
 HidConnection::~HidConnection() {}
 
-const HidDeviceInfo& HidConnection::device_info() const {
-  return device_info_;
-}
-
 }  // namespace device