Threaded data provider: Support main thread data notifications (Blink side)

public/platform/WebThreadedDataReceiver.h

 // 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.
 
 #ifndef WebThreadedDataReceiver_h
 #define WebThreadedDataReceiver_h
 
 namespace blink {
 
 class WebThread;
 
 class WebThreadedDataReceiver {
 public:
     virtual void acceptData(const char* data, int dataLength) = 0;
     virtual WebThread* backgroundThread() = 0;
 
+    virtual bool needsMainthreadDataCopy() = 0;
+    virtual void acceptMainthreadDataNotification(const char* data, int dataLength, int encodedDataLength) = 0;
+
     virtual ~WebThreadedDataReceiver() { }
 };
 
 } // namespace blink
 
 #endif