diff --git a/Source/WebCore/dom/WebKitNamedFlowCollection.cpp b/Source/WebCore/dom/WebKitNamedFlowCollection.cpp
new file mode 100644
index 0000000..b0cff11
--- /dev/null
+++ b/Source/WebCore/dom/WebKitNamedFlowCollection.cpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer.
+ * 2. Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+ * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+ * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "WebKitNamedFlowCollection.h"
+
+#include "Document.h"
+#include "WebKitNamedFlow.h"
+
+#include <wtf/text/StringHash.h>
+#include <wtf/text/WTFString.h>
+
+namespace WebCore {
+
+WebKitNamedFlowCollection::WebKitNamedFlowCollection(Document* doc)
+    : m_document(doc)
+{
+}
+
+WebKitNamedFlow* WebKitNamedFlowCollection::flowByName(const String& flowName)
+{
+    NamedFlowSet::iterator it = m_namedFlows.find<String, NamedFlowHashTranslator>(flowName);
+    if (it == m_namedFlows.end() || (*it)->flowState() == WebKitNamedFlow::FlowStateNull)
+        return 0;
+
+    return *it;
+}
+
+PassRefPtr<WebKitNamedFlow> WebKitNamedFlowCollection::ensureFlowWithName(const String& flowName)
+{
+    NamedFlowSet::iterator it = m_namedFlows.find<String, NamedFlowHashTranslator>(flowName);
+    if (it != m_namedFlows.end()) {
+        WebKitNamedFlow* namedFlow = *it;
+        ASSERT(namedFlow->flowState() == WebKitNamedFlow::FlowStateNull);
+
+        return namedFlow;
+    }
+
+    RefPtr<WebKitNamedFlow> newFlow = WebKitNamedFlow::create(this, flowName);
+    m_namedFlows.add(newFlow.get());
+
+    return newFlow.release();
+}
+
+void WebKitNamedFlowCollection::discardNamedFlow(WebKitNamedFlow* namedFlow)
+{
+    // The document is not valid anymore so the collection will be destroyed anyway.
+    if (!m_document)
+        return;
+
+    ASSERT(namedFlow->flowState() == WebKitNamedFlow::FlowStateNull);
+    ASSERT(m_namedFlows.contains(namedFlow));
+
+    m_namedFlows.remove(namedFlow);
+}
+
+void WebKitNamedFlowCollection::documentDestroyed()
+{
+    m_document = 0;
+}
+
+// The HashFunctions object used by the HashSet to compare between NamedFlows.
+// It is safe to set safeToCompareToEmptyOrDeleted because the HashSet will never contain null pointers or deleted values.
+struct WebKitNamedFlowCollection::NamedFlowHashFunctions {
+    static unsigned hash(WebKitNamedFlow* key) { return DefaultHash<String>::Hash::hash(key->name()); }
+    static bool equal(WebKitNamedFlow* a, WebKitNamedFlow* b) { return a->name() == b->name(); }
+    static const bool safeToCompareToEmptyOrDeleted = true;
+};
+
+// The HashTranslator is used to lookup a NamedFlow in the set using a name.
+struct WebKitNamedFlowCollection::NamedFlowHashTranslator {
+    static unsigned hash(const String& key) { return DefaultHash<String>::Hash::hash(key); }
+    static bool equal(WebKitNamedFlow* a, const String& b) { return a->name() == b; }
+};
+
+} // namespace WebCore