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

public/platform/WebThreadedDataReceiver.h

Index: public/platform/WebThreadedDataReceiver.h
diff --git a/public/platform/WebThreadedDataReceiver.h b/public/platform/WebThreadedDataReceiver.h
index df78e9cdc28c69346e561b6d70ed3176a4ea4874..516c13b870bc61b75e539c13ee153172a7cafa3c 100644
--- a/public/platform/WebThreadedDataReceiver.h
+++ b/public/platform/WebThreadedDataReceiver.h
@@ -14,6 +14,9 @@ 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() { }
 };