Expose Gamepad API instance for Cardboard button

device/vr/BUILD.gn

 # Copyright 2016 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.
 
 import("features/features.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")  # For generate_jni().
 }
@@ skipping 27 matching lines @@
 
     deps += [
       "//base",
       "//gpu/ipc/common:interfaces",
       "//mojo/public/cpp/bindings",
       "//ui/gfx",
     ]
 
     if (is_android && (current_cpu == "arm" || current_cpu == "arm64")) {
       sources += [
+        "android/gvr/cardboard_gamepad_data_fetcher.cc",
+        "android/gvr/cardboard_gamepad_data_fetcher.h",
+        "android/gvr/cardboard_gamepad_data_provider.h",
         "android/gvr/gvr_delegate.cc",
         "android/gvr/gvr_delegate.h",
         "android/gvr/gvr_delegate_provider.cc",
         "android/gvr/gvr_delegate_provider.h",
         "android/gvr/gvr_device.cc",
         "android/gvr/gvr_device.h",
         "android/gvr/gvr_device_provider.cc",
         "android/gvr/gvr_device_provider.h",
         "android/gvr/gvr_gamepad_data_fetcher.cc",
         "android/gvr/gvr_gamepad_data_fetcher.h",
@@ skipping 66 matching lines @@
   ]
 
   public_deps = [
     "//gpu/ipc/common:interfaces",
     "//mojo/common:common_custom_types",
   ]
 
   # TODO(crbug.com/714018): Convert the implementation to use OnceCallback.
   use_once_callback = false
 }