Reland: BackgroundHTMLParser: Introduce ParsedChunkQueue to pass ParsedChunks to main thread

third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.h

Index: third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.h
diff --git a/third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.h b/third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.h
new file mode 100644
index 0000000000000000000000000000000000000000..1a4427061bd90f1f650290ae58f4812796cd0fca
--- /dev/null
+++ b/third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.h
@@ -0,0 +1,51 @@
+// Copyright 2015 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 ParsedChunkQueue_h
+#define ParsedChunkQueue_h
+
+#include "core/html/parser/HTMLDocumentParser.h"
+#include "wtf/Deque.h"
+#include "wtf/OwnPtr.h"
+#include "wtf/PassOwnPtr.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefPtr.h"
+#include "wtf/ThreadSafeRefCounted.h"
+#include "wtf/ThreadingPrimitives.h"
+#include "wtf/Vector.h"
+
+namespace blink {
+
+// ParsedChunkQueue is used to transfer parsed HTML token chunks
+// from BackgroundHTMLParser thread to Blink main thread without
+// spamming task queue.
+// ParsedChunkQueue is accessed from both BackgroundHTMLParser
+// thread (producer) and Blink main thread (consumer).
+// Access to the backend queue vector is protected by a mutex.
+// If enqueue is done against empty queue, BackgroundHTMLParser
+// thread kicks a consumer task on Blink main thread.
+class ParsedChunkQueue : public ThreadSafeRefCounted<ParsedChunkQueue> {
+public:
+    static PassRefPtr<ParsedChunkQueue> create()
+    {
+        return adoptRef(new ParsedChunkQueue);
+    }
+
+    ~ParsedChunkQueue();
+
+    bool enqueue(PassOwnPtr<HTMLDocumentParser::ParsedChunk>);
+    void clear();
+
+    void takeAll(Vector<OwnPtr<HTMLDocumentParser::ParsedChunk>>&);
+
+private:
+    ParsedChunkQueue();
+
+    Mutex m_mutex;
+    Vector<OwnPtr<HTMLDocumentParser::ParsedChunk>> m_pendingChunks;
+};
+
+} // namespace blink
+
+#endif