Add component for feature engagement tracking.

components/feature_engagement_tracker/public/android/feature_engagement_tracker_jni_registrar.h

+// 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.
+
+#ifndef COMPONENTS_FEATURE_ENGAGEMENT_TRACKER_PUBLIC_ANDROID_FEATURE_ENGAGEMENT_TRACKER_JNI_REGISTRAR_H_
+#define COMPONENTS_FEATURE_ENGAGEMENT_TRACKER_PUBLIC_ANDROID_FEATURE_ENGAGEMENT_TRACKER_JNI_REGISTRAR_H_
+
+#include "base/android/jni_android.h"
+
+namespace feature_engagement_tracker {
+
+// Register the FeatureEngagementTracker's native methods through JNI.
+bool RegisterFeatureEngagementTrackerJni(JNIEnv* env);
+
+}  // namespace feature_engagement_tracker
+
+#endif  // COMPONENTS_FEATURE_ENGAGEMENT_TRACKER_PUBLIC_ANDROID_FEATURE_ENGAGEMENT_TRACKER_JNI_REGISTRAR_H_