Apply the same hack as conversion to prediction for transition cost from history node

Sometimes transition cost is too high and causes a bug Issue 274.

For example, "接続詞 が" -> "始まる 動詞,五段活用,基本形" has very large cost and "始まる" is demoted.  To prevent such cases, ImmutableConverter computes transition from BOS/EOS too; see ImmutableConverterImpl::MakeLatticeNodesForHistorySegments().

This CL introduces the same hack for DictionaryPredictor::GetLMCost so that similar language model can be applied to both suggestion candidates and conversion candidates.

Closes Issue 274.

BUG=Issue mozc:274

git-svn-id: a6090854-d499-a067-5803-1114d4e51264
5 files changed
tree: 550640c3c00d955be7395f2c39a09a08b2731d4c
  1. src/