Fix a bug with surrogate pairs

Bug: 10316781
Change-Id: I528c59c8823cda11975cb01b0ae59f12cfadef3b
diff --git a/java/src/com/android/inputmethod/latin/LatinIME.java b/java/src/com/android/inputmethod/latin/LatinIME.java
index 08a5429..5323f2b 100644
--- a/java/src/com/android/inputmethod/latin/LatinIME.java
+++ b/java/src/com/android/inputmethod/latin/LatinIME.java
@@ -2555,8 +2555,8 @@
             }
         }
         mWordComposer.setComposingWord(typedWord, mKeyboardSwitcher.getKeyboard());
-        // TODO: this is in chars but the callee expects code points!
-        mWordComposer.setCursorPositionWithinWord(numberOfCharsInWordBeforeCursor);
+        mWordComposer.setCursorPositionWithinWord(
+                typedWord.codePointCount(0, numberOfCharsInWordBeforeCursor));
         mConnection.setComposingRegion(
                 mLastSelectionStart - numberOfCharsInWordBeforeCursor,
                 mLastSelectionEnd + range.getNumberOfCharsInWordAfterCursor());