Add getDictDecoder.

...com/android/inputmethod/latin/BinaryDictionaryGetter.java

...android/inputmethod/latin/makedict/BinaryDictIOUtils.java

...c/com/android/inputmethod/latin/makedict/DictDecoder.java

...rc/com/android/inputmethod/latin/makedict/FormatSpec.java

...m/android/inputmethod/latin/makedict/Ver3DictDecoder.java

...atin/personalization/DynamicPredictionDictionaryBase.java

...droid/inputmethod/latin/utils/UserHistoryDictIOUtils.java

...tmethod/latin/makedict/BinaryDictDecoderEncoderTests.java

...id/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java

.../inputmethod/latin/utils/UserHistoryDictIOUtilsTests.java

.../inputmethod/latin/dicttool/BinaryDictOffdeviceUtils.java

...m/android/inputmethod/latin/dicttool/DictionaryMaker.java

...tmethod/latin/dicttool/BinaryDictOffdeviceUtilsTests.java