Remove unused fromVLQSigned function (#402)

This is a leftover from #306.

Author: jridgewell

lib/base64-vlq.js

@@ -72,21 +72,6 @@ function toVLQSigned(aValue) {
     : (aValue << 1) + 0;
 }
 
-/**
- * Converts to a two-complement value from a value where the sign bit is
- * placed in the least significant bit.  For example, as decimals:
- *   2 (10 binary) becomes 1, 3 (11 binary) becomes -1
- *   4 (100 binary) becomes 2, 5 (101 binary) becomes -2
- */
-// eslint-disable-next-line no-unused-vars
-function fromVLQSigned(aValue) {
-  const isNegative = (aValue & 1) === 1;
-  const shifted = aValue >> 1;
-  return isNegative
-    ? -shifted
-    : shifted;
-}
-
 /**
  * Returns the base 64 VLQ encoded value.
  */