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

components/gcm_driver/instance_id/scoped_use_fake_instance_id_android.cc

+// 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/scoped_use_fake_instance_id_android.h"
+
+#include "base/android/jni_android.h"
+#include "jni/FakeInstanceIDWithSubtype_jni.h"
+
+using base::android::AttachCurrentThread;
+
+namespace instance_id {
+
+// static
+bool ScopedUseFakeInstanceIDAndroid::RegisterJni(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+ScopedUseFakeInstanceIDAndroid::ScopedUseFakeInstanceIDAndroid() {
+  JNIEnv* env = AttachCurrentThread();
+  previous_value_ =
+      Java_FakeInstanceIDWithSubtype_clearDataAndSetEnabled(env, true);
+}
+
+ScopedUseFakeInstanceIDAndroid::~ScopedUseFakeInstanceIDAndroid() {
+  JNIEnv* env = AttachCurrentThread();
+  Java_FakeInstanceIDWithSubtype_clearDataAndSetEnabled(env, previous_value_);
+}
+
+}  // namespace instance_id