Bug 934142, remove faulty assertion. r=khuey.

dom/ipc/Blob.cpp

@@ -1080,10 +1080,6 @@ RemoteBlob<Parent>::MaybeSetInputStream(const ConstructorParamsType& aParams)
     mInputStreamParams =
       aParams.optionalInputStreamParams().get_InputStreamParams();
   }
-  else {
-    MOZ_ASSERT(aParams.blobParams().type() ==
-               ChildBlobConstructorParams::TMysteryBlobConstructorParams);
-  }
 }
 
 template <>