diff -r 000000000000 -r 6474c204b198 parser/html/nsHtml5DependentUTF16Buffer.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parser/html/nsHtml5DependentUTF16Buffer.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsHtml5DependentUTF16Buffer.h"
+
+nsHtml5DependentUTF16Buffer::nsHtml5DependentUTF16Buffer(const nsAString& aToWrap)
+  : nsHtml5UTF16Buffer(const_cast<char16_t*> (aToWrap.BeginReading()),
+                       aToWrap.Length())
+{
+  MOZ_COUNT_CTOR(nsHtml5DependentUTF16Buffer);
+}
+
+nsHtml5DependentUTF16Buffer::~nsHtml5DependentUTF16Buffer()
+{
+  MOZ_COUNT_DTOR(nsHtml5DependentUTF16Buffer);
+}
+
+already_AddRefed<nsHtml5OwningUTF16Buffer>
+nsHtml5DependentUTF16Buffer::FalliblyCopyAsOwningBuffer()
+{
+  int32_t newLength = getEnd() - getStart();
+  nsRefPtr<nsHtml5OwningUTF16Buffer> newObj =
+    nsHtml5OwningUTF16Buffer::FalliblyCreate(newLength);
+  if (!newObj) {
+    return nullptr;
+  }
+  newObj->setEnd(newLength);
+  memcpy(newObj->getBuffer(),
+         getBuffer() + getStart(),
+         newLength * sizeof(char16_t));
+  return newObj.forget();
+}