Handle push resubscribes with no sender info (avoids DCHECK)

chrome/test/data/push_messaging/push_test.js

Index: chrome/test/data/push_messaging/push_test.js
diff --git a/chrome/test/data/push_messaging/push_test.js b/chrome/test/data/push_messaging/push_test.js
index 180f1a622860570361433804d1dc4c6b9e53575f..0ca431a336287de698c58f28c02e5ae6ac94fbca 100644
--- a/chrome/test/data/push_messaging/push_test.js
+++ b/chrome/test/data/push_messaging/push_test.js
@@ -119,6 +119,18 @@ function documentSubscribePush() {
   }).catch(sendErrorToTest);
 }
 
+function documentSubscribePushWithNumber() {

[harkness, 2016/11/02 18:48:12]

nit NumericKey ?

[awdf, 2016/11/03 14:10:11]

Done.

+  navigator.serviceWorker.ready.then(function(swRegistration) {
+    return swRegistration.pushManager.subscribe({
+          userVisibleOnly: true,
+          applicationServerKey: new TextEncoder().encode('1234567890')
+        })
+        .then(function(subscription) {
+          sendResultToTest(subscription.endpoint);
+        });
+  }).catch(sendErrorToTest);
+}
+
 function workerSubscribePush() {
   // Send the message to the worker for it to subscribe
   navigator.serviceWorker.controller.postMessage({command: 'workerSubscribe'});
@@ -131,6 +143,12 @@ function workerSubscribePushNoKey() {
       {command: 'workerSubscribeNoKey'});
 }
 
+function workerSubscribePushWithNumber() {
+  // Send the message to the worker for it to subscribe
+  navigator.serviceWorker.controller.postMessage(
+      {command: 'workerSubscribeWithNumber'});
+}
+
 function GetP256dh() {
   navigator.serviceWorker.ready.then(function(swRegistration) {
     return swRegistration.pushManager.getSubscription()