[Device Service] Move Gamepad Blink headers to be part of the Gamepad client library

device/gamepad/public/cpp/gamepad.cc

Index: device/gamepad/public/cpp/gamepad.cc
diff --git a/device/gamepad/public/cpp/gamepad.cc b/device/gamepad/public/cpp/gamepad.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bd5bf4ed77c02c7dbe81f70de98b907d74a05d1c
--- /dev/null
+++ b/device/gamepad/public/cpp/gamepad.cc
@@ -0,0 +1,21 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "device/gamepad/public/cpp/gamepad.h"
+
+namespace device {
+
+Gamepad::Gamepad()
+    : connected(false),
+      timestamp(0),
+      axes_length(0),
+      buttons_length(0),
+      display_id(0) {
+  id[0] = 0;
+  mapping[0] = 0;
+}
+
+Gamepad::Gamepad(const Gamepad& other) = default;
+
+}  // namespace device