Add fake for InstanceIDWithSubtype.java, in order to re-use unit test

components/gcm_driver/instance_id/instance_id_test_utils_android.cc

Index: components/gcm_driver/instance_id/instance_id_test_utils_android.cc
diff --git a/components/gcm_driver/instance_id/instance_id_test_utils_android.cc b/components/gcm_driver/instance_id/instance_id_test_utils_android.cc
new file mode 100644
index 0000000000000000000000000000000000000000..148c56f710e963c24d8a531b57041a7563a05e56
--- /dev/null
+++ b/components/gcm_driver/instance_id/instance_id_test_utils_android.cc
@@ -0,0 +1,26 @@
+// 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.
+
+#include "components/gcm_driver/instance_id/instance_id_test_utils_android.h"
+
+#include "base/android/jni_android.h"
+#include "jni/FakeInstanceIDWithSubtype_jni.h"
+
+using base::android::AttachCurrentThread;
+
+namespace instance_id {
+
+// static
+bool InstanceIDTestUtilsAndroid::RegisterJni(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+// static
+void InstanceIDTestUtilsAndroid::ClearDataAndSetUseFakeForTesting(
+    bool use_fake) {
+  JNIEnv* env = AttachCurrentThread();
+  Java_FakeInstanceIDWithSubtype_clearDataAndSetEnabled(env, use_fake);
+}
+
+}  // namespace instance_id