Add CollectionUtils class to create generic collection easily

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

...c/com/android/inputmethod/compat/SuggestionSpanUtils.java

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

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

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

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

.../android/inputmethod/keyboard/internal/KeySpecParser.java

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

...droid/inputmethod/keyboard/internal/KeyboardCodesSet.java

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

...droid/inputmethod/keyboard/internal/KeyboardTextsSet.java

...id/inputmethod/keyboard/internal/PointerTrackerQueue.java

.../src/com/android/inputmethod/latin/AdditionalSubtype.java

.../android/inputmethod/latin/AdditionalSubtypeSettings.java

java/src/com/android/inputmethod/latin/BinaryDictionary.java

...android/inputmethod/latin/BinaryDictionaryFileDumper.java

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

java/src/com/android/inputmethod/latin/CollectionUtils.java

...c/com/android/inputmethod/latin/DictionaryCollection.java

.../src/com/android/inputmethod/latin/DictionaryFactory.java