Update the PushEvent to have a nullable PushMessageData

third_party/WebKit/Source/modules/push_messaging/PushMessageData.cpp

 // 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.
 
 #include "modules/push_messaging/PushMessageData.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/modules/v8/UnionTypesModules.h"
 #include "core/dom/DOMArrayBuffer.h"
 #include "core/fileapi/Blob.h"
 #include "platform/blob/BlobData.h"
 #include "wtf/text/TextEncoding.h"
 #include <v8.h>
 
 namespace blink {
 
 PushMessageData* PushMessageData::create(const String& messageString)
 {
+    // The standard supports both an empty but valid message and a null message.
+    // In case the message is explicitly null, return a null pointer which will
+    // be set in the PushEvent.
+    if (messageString.isNull())
+        return nullptr;
     return PushMessageData::create(ArrayBufferOrArrayBufferViewOrUSVString::fromUSVString(messageString));
 }
 
 PushMessageData* PushMessageData::create(const ArrayBufferOrArrayBufferViewOrUSVString& messageData)
 {
     if (messageData.isArrayBuffer() || messageData.isArrayBufferView()) {
         RefPtr<DOMArrayBuffer> buffer = messageData.isArrayBufferView()
             ? messageData.getAsArrayBufferView()->buffer()
             : messageData.getAsArrayBuffer();
 
@@ skipping 59 matching lines @@
 String PushMessageData::text() const
 {
     return UTF8Encoding().decode(m_data.data(), m_data.size());
 }
 
 DEFINE_TRACE(PushMessageData)
 {
 }
 
 } // namespace blink