Implement the skeleton of an android content shell.

content/browser/android/jni_helper.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[jam, 2012/04/19 21:56:26]

I'm not familiar with android or jni, but it's not clear to me that these files
belong in content/browser. who's the intended consumer, just content_shell? if
so, why not keep them there? if chrome as well, well it can't access code in
content/browser since that's not in the public directory. or perhaps this stuff
just belongs in base/android with the rest of the android files there?

[Ted C, 2012/04/20 01:14:14]

Done...for now it better belongs in base.  If we we need to tweak this later, we
certainly can.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_ANDROID_JNI_HELPER_H_
+#define CONTENT_BROWSER_ANDROID_JNI_HELPER_H_
+
+#include <jni.h>
+
+#include "base/android/scoped_java_ref.h"
+
+struct RegistrationMethod {
+  const char* name;
+  bool (*func)(JNIEnv* env);
+};
+
+// Manages WeakGlobalRef lifecycle.
+class JavaObjectWeakGlobalRef {
+ public:
+  JavaObjectWeakGlobalRef(JNIEnv* env, jobject obj);
+  virtual ~JavaObjectWeakGlobalRef();
+
+  base::android::ScopedJavaLocalRef<jobject> get(JNIEnv* env) const;
+
+ private:
+  jweak obj_;
+
+  DISALLOW_COPY_AND_ASSIGN(JavaObjectWeakGlobalRef);
+};
+
+// Get the real object stored in the weak reference returned as a
+// ScopedJavaLocalRef.
+base::android::ScopedJavaLocalRef<jobject> GetRealObject(
+    JNIEnv* env, jobject obj);
+
+#endif  // CONTENT_BROWSER_ANDROID_JNI_HELPER_H_