Partial implementation of subscription restrictions.

third_party/WebKit/public/platform/modules/push_messaging/WebPushSubscriptionOptions.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 WebPushSubscriptionOptions_h
 #define WebPushSubscriptionOptions_h
 
+#include "public/platform/WebString.h"
+
 namespace blink {
 
 struct WebPushSubscriptionOptions {
     WebPushSubscriptionOptions()
         : userVisibleOnly(false)
     {
     }
 
     // Indicates that the subscription will only be used for push messages
     // that result in UI visible to the user.
     bool userVisibleOnly;
+
+    // Public key of the app server that can send push messages to this
+    // subscription.

[Peter Beverloo, 2016/02/17 16:15:36]

Since it expects a specific format (uncompressed EC points), it would be good to
detail this in the comment:

  // P-256 public key, in uncompressed form, of the app server that can send
  // push messages to this subscription.

[harkness, 2016/02/18 10:45:15]

Done.

+    WebString applicationServerKey;
 };
 
 } // namespace blink
 
 #endif // WebPushSubscriptionOptions_h