Bug 1305826: P1. Fix move constructor. r=gerald

With a const input, the object would never be moved but copied instead

MozReview-Commit-ID: 7VUJDLCxOQJ

--HG--
extra : rebase_source : de77074cc9c6632c82dcbdec242e2692f7790a66

dom/media/AudioConverter.h

@@ -84,7 +84,7 @@ public:
     static_assert(Format == AudioConfig::FORMAT_S16,
                   "Conversion not implemented yet");
   }
-  explicit AudioDataBuffer(const AlignedFloatBuffer&& aBuffer)
+  explicit AudioDataBuffer(AlignedFloatBuffer&& aBuffer)
     : mBuffer(Move(aBuffer))
   {
     static_assert(Format == AudioConfig::FORMAT_FLT,