Android: Remove unneeded RegisterNatives() calls

ui/events/android/key_event_utils.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 UI_EVENTS_ANDROID_KEY_EVENT_UTILS_H_
 #define UI_EVENTS_ANDROID_KEY_EVENT_UTILS_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
 #include "ui/events/events_export.h"
 
 namespace ui {
 namespace events {
 namespace android {
 
-bool RegisterKeyEvent(JNIEnv* env);
-
 EVENTS_EXPORT base::android::ScopedJavaLocalRef<jobject>
 CreateKeyEvent(JNIEnv* env, int action, int key_code);
 
 EVENTS_EXPORT int GetKeyEventUnicodeChar(
     JNIEnv* env,
     const base::android::JavaRef<jobject>& event,
     int meta_state);
 
 }  // namespace android
 }  // namespace events
 }  // namespace ui
 
 #endif  // UI_EVENTS_ANDROID_KEY_EVENT_UTISL_H_