Add a JNI to get the frequency

Bug: 4192129
Change-Id: I3f220f5a10114d4eb23956148076cf76220bda0f
diff --git a/native/jni/src/dictionary.h b/native/jni/src/dictionary.h
index 87891ee..9f23679 100644
--- a/native/jni/src/dictionary.h
+++ b/native/jni/src/dictionary.h
@@ -52,7 +52,7 @@
                 maxWordLength, maxBigrams);
     }
 
-    bool isValidWord(const int32_t *word, int length);
+    int getFrequency(const int32_t *word, int length);
     bool isValidBigram(const int32_t *word1, int length1, const int32_t *word2, int length2);
     void *getDict() { return (void *)mDict; }
     int getDictSize() { return mDictSize; }