Use SparseArray<E> instead of HashMap<Integer,E>

...d/inputmethod/accessibility/KeyCodeDescriptionMapper.java

java/src/com/android/inputmethod/keyboard/Keyboard.java

...c/com/android/inputmethod/keyboard/KeyboardLayoutSet.java

java/src/com/android/inputmethod/keyboard/KeyboardView.java

java/src/com/android/inputmethod/keyboard/ProximityInfo.java

.../com/android/inputmethod/keyboard/internal/KeyStyles.java

...droid/inputmethod/keyboard/internal/KeyboardIconsSet.java