message: Support CharChunks with command keys only.
diff: @@ -98,7 +98,13 @@ size_t Composition::InsertInput(size_t pos, const CompositionInput &input) {
  }
  CharChunkList::iterator right_chunk = MaybeSplitChunkAt(pos);
  + while (right_chunk != chunks_.end() &&
  + (*right_chunk)->GetLength(input_t12r_) == 0) {
  + ++right_chunk;
  + }
  +
  CharChunkList::iterator left_chunk = GetInsertionChunk(right_chunk);
  +
  CombinePendingChunks(left_chunk, input);
  CompositionInput mutable_input = input;
  