diff -r 000000000000 -r 6474c204b198 dom/encoding/TextEncoder.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/encoding/TextEncoder.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,102 @@
+/* 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 "mozilla/dom/TextEncoder.h"
+#include "mozilla/dom/EncodingUtils.h"
+#include "nsContentUtils.h"
+
+namespace mozilla {
+namespace dom {
+
+void
+TextEncoder::Init(const nsAString& aEncoding, ErrorResult& aRv)
+{
+  nsAutoString label(aEncoding);
+  EncodingUtils::TrimSpaceCharacters(label);
+
+  // Let encoding be the result of getting an encoding from label.
+  // If encoding is failure, or is none of utf-8, utf-16, and utf-16be,
+  // throw a TypeError.
+  if (!EncodingUtils::FindEncodingForLabel(label, mEncoding)) {
+    aRv.ThrowTypeError(MSG_ENCODING_NOT_SUPPORTED, &label);
+    return;
+  }
+
+  if (!mEncoding.EqualsLiteral("UTF-8") &&
+      !mEncoding.EqualsLiteral("UTF-16LE") &&
+      !mEncoding.EqualsLiteral("UTF-16BE")) {
+    aRv.ThrowTypeError(MSG_DOM_ENCODING_NOT_UTF);
+    return;
+  }
+
+  // Create an encoder object for mEncoding.
+  mEncoder = EncodingUtils::EncoderForEncoding(mEncoding);
+}
+
+void
+TextEncoder::Encode(JSContext* aCx,
+                    JS::Handle<JSObject*> aObj,
+                    const nsAString& aString,
+                    const bool aStream,
+		    JS::MutableHandle<JSObject*> aRetval,
+                    ErrorResult& aRv)
+{
+  // Run the steps of the encoding algorithm.
+  int32_t srcLen = aString.Length();
+  int32_t maxLen;
+  const char16_t* data = PromiseFlatString(aString).get();
+  nsresult rv = mEncoder->GetMaxLength(data, srcLen, &maxLen);
+  if (NS_FAILED(rv)) {
+    aRv.Throw(rv);
+    return;
+  }
+  // Need a fallible allocator because the caller may be a content
+  // and the content can specify the length of the string.
+  static const fallible_t fallible = fallible_t();
+  nsAutoArrayPtr<char> buf(new (fallible) char[maxLen + 1]);
+  if (!buf) {
+    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+    return;
+  }
+
+  int32_t dstLen = maxLen;
+  rv = mEncoder->Convert(data, &srcLen, buf, &dstLen);
+
+  // If the internal streaming flag is not set, then reset
+  // the encoding algorithm state to the default values for encoding.
+  if (!aStream) {
+    int32_t finishLen = maxLen - dstLen;
+    rv = mEncoder->Finish(buf + dstLen, &finishLen);
+    if (NS_SUCCEEDED(rv)) {
+      dstLen += finishLen;
+    }
+  }
+
+  JSObject* outView = nullptr;
+  if (NS_SUCCEEDED(rv)) {
+    buf[dstLen] = '\0';
+    JSAutoCompartment ac(aCx, aObj);
+    outView = Uint8Array::Create(aCx, dstLen,
+                                 reinterpret_cast<uint8_t*>(buf.get()));
+    if (!outView) {
+      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+      return;
+    }
+  }
+
+  if (NS_FAILED(rv)) {
+    aRv.Throw(rv);
+  }
+  aRetval.set(outView);
+}
+
+void
+TextEncoder::GetEncoding(nsAString& aEncoding)
+{
+  CopyASCIItoUTF16(mEncoding, aEncoding);
+  nsContentUtils::ASCIIToLower(aEncoding);
+}
+
+} // dom
+} // mozilla