diff -r 000000000000 -r 6474c204b198 netwerk/base/src/nsBase64Encoder.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netwerk/base/src/nsBase64Encoder.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,67 @@
+/* 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 "nsBase64Encoder.h"
+
+#include "plbase64.h"
+#include "prmem.h"
+
+NS_IMPL_ISUPPORTS(nsBase64Encoder, nsIOutputStream)
+
+NS_IMETHODIMP
+nsBase64Encoder::Close()
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBase64Encoder::Flush()
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBase64Encoder::Write(const char* aBuf, uint32_t aCount, uint32_t* _retval)
+{
+  mData.Append(aBuf, aCount);
+  *_retval = aCount;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBase64Encoder::WriteFrom(nsIInputStream* aStream, uint32_t aCount,
+                           uint32_t* _retval)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsBase64Encoder::WriteSegments(nsReadSegmentFun aReader,
+                               void* aClosure,
+                               uint32_t aCount,
+                               uint32_t* _retval)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsBase64Encoder::IsNonBlocking(bool* aNonBlocking)
+{
+  *aNonBlocking = false;
+  return NS_OK;
+}
+
+nsresult
+nsBase64Encoder::Finish(nsCSubstring& result)
+{
+  char* b64 = PL_Base64Encode(mData.get(), mData.Length(), nullptr);
+  if (!b64)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  result.Assign(b64);
+  PR_Free(b64);
+  // Free unneeded memory and allow reusing the object
+  mData.Truncate();
+  return NS_OK;
+}