Android: support http referrers for context menu navigations.

content/public/android/java/src/org/chromium/content_public/Referrer.java

+// Copyright 2014 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.
+
+package org.chromium.content_public;
+
+/**
+ * Container that holds together a referrer URL along with the referrer policy set on the
+ * originating frame. This corresponds to native content/public/common/referrer.h.
+ */
+public class Referrer {
+    private final String mUrl;
+    private final int mPolicy;
+
+    public Referrer(String url, int policy) {
+        mUrl = url;
+        mPolicy = policy;
+    }
+
+    public String getUrl() {
+        return mUrl;
+    }
+
+    public int getPolicy() {
+        return mPolicy;
+    }
+}