Separate JNI registration with initialization

base/android/jni_onload_delegate.h

+// Copyright 2015 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_JNI_ONLOAD_DELEGATE_H_
+#define BASE_ANDROID_JNI_ONLOAD_DELEGATE_H_
+
+#include <jni.h>
+
+#include "base/base_export.h"
+
+namespace base {
+namespace android {
+
+// This delegate class is used to implement component specific JNI registration
+// and initialization. All methods are called in JNI_OnLoad().
+//
+// Both RegisterJNI() and Init() methods are called if the shared library
+// is loaded by crazy linker that can't find JNI methods without JNI
+// registration, otherwise, only Init() is invoked where dynamic lookup is
+// used to find the JNI methods.
+//
+// It is important to make sure the JNI registration code is only in
+// RegisterJNI(), so it could be stripped out when JNI registration isn't
+// needed.
+class BASE_EXPORT JNIOnLoadDelegate {
+ public:
+  virtual ~JNIOnLoadDelegate() {}
+
+  // Returns whether the JNI registration succeeded.
+  virtual bool RegisterJNI(JNIEnv* env) = 0;
+
+  // Returns whether the initialization succeeded. This method is called after
+  // RegisterJNI(), all JNI methods shall ready to be used.
+  virtual bool Init() = 0;
+};
+
+}  // namespace android
+}  // namespace base
+
+#endif  // BASE_ANDROID_JNI_ONLOAD_DELEGATE_H_