Add support for calling the java Callback from native.

base/android/callback_android.h

+// 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.
+
+#ifndef BASE_ANDROID_CALLBACK_ANDROID_H_
+#define BASE_ANDROID_CALLBACK_ANDROID_H_
+
+#include <jni.h>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/base_export.h"
+
+namespace base {
+namespace android {
+
+// Runs the given |callback| with the specified |arg|.
+void BASE_EXPORT RunCallbackAndroid(const JavaRef<jobject>& callback,
+                                    const JavaRef<jobject>& arg);
+
+// Runs the given |callback| with the specified |arg|.
+void BASE_EXPORT RunCallbackAndroid(const JavaRef<jobject>& callback,
+                                    bool arg);
+
+// JNI registration boilerplate.
+bool RegisterCallbackAndroid(JNIEnv* env);
+
+}  // namespace android
+}  // namespace base
+
+#endif  // BASE_ANDROID_CALLBACK_ANDROID_H_