diff -r 000000000000 -r 6474c204b198 extensions/universalchardet/src/base/nsUTF8Prober.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/extensions/universalchardet/src/base/nsUTF8Prober.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,55 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsUTF8Prober.h"
+
+void  nsUTF8Prober::Reset(void)
+{
+  mCodingSM->Reset(); 
+  mNumOfMBChar = 0;
+  mState = eDetecting;
+}
+
+nsProbingState nsUTF8Prober::HandleData(const char* aBuf, uint32_t aLen)
+{
+  nsSMState codingState;
+
+  for (uint32_t i = 0; i < aLen; i++)
+  {
+    codingState = mCodingSM->NextState(aBuf[i]);
+    if (codingState == eItsMe)
+    {
+      mState = eFoundIt;
+      break;
+    }
+    if (codingState == eStart)
+    {
+      if (mCodingSM->GetCurrentCharLen() >= 2)
+        mNumOfMBChar++;
+    }
+  }
+
+  if (mState == eDetecting)
+    if (GetConfidence() > SHORTCUT_THRESHOLD)
+      mState = eFoundIt;
+  return mState;
+}
+
+#define ONE_CHAR_PROB   (float)0.50
+
+float nsUTF8Prober::GetConfidence(void)
+{
+  float unlike = (float)0.99;
+
+  if (mNumOfMBChar < 6)
+  {
+    for (uint32_t i = 0; i < mNumOfMBChar; i++)
+      unlike *= ONE_CHAR_PROB;
+    return (float)1.0 - unlike;
+  }
+  else
+    return (float)0.99;
+}
+