Script streaming: Add an option to make the main thread block (wait for parsing)

Source/bindings/core/v8/ScriptStreamerThread.cpp

Index: Source/bindings/core/v8/ScriptStreamerThread.cpp
diff --git a/Source/bindings/core/v8/ScriptStreamerThread.cpp b/Source/bindings/core/v8/ScriptStreamerThread.cpp
index c706ad118476d4be1e4377f8998a0f749693d065..16fe74231ec2232c339d031c571947389eba9f28 100644
--- a/Source/bindings/core/v8/ScriptStreamerThread.cpp
+++ b/Source/bindings/core/v8/ScriptStreamerThread.cpp
@@ -67,9 +67,7 @@ void ScriptStreamingTask::run()
     // Running the task can and will block: SourceStream::GetSomeData will get
     // called and it will block and wait for data from the network.
     m_v8Task->Run();
-    // Post a task to the main thread to signal that V8 has completed the
-    // streaming.
-    callOnMainThread(WTF::bind(&ScriptStreamer::streamingComplete, m_streamer));
+    m_streamer->streamingCompleteOnBackgroundThread();
     ScriptStreamerThread::shared()->taskDone();
 }