Fix build warnings about improper ASCII encoding.

 *

 * <p>The screen density of a device is based on the screen resolution. A screen with low density

 * has fewer available pixels per inch, where a screen with high density

 * has more — sometimes significantly more — pixels per inch. The density of a

 * has more - sometimes significantly more - pixels per inch. The density of a

 * screen is important because, other things being equal, a UI element (such as a button) whose

 * height and width are defined in terms of screen pixels will appear larger on the lower density

 * screen and smaller on the higher density screen.