Doc fix: add more detail to BitmapFactory.Options.inPurgeable flag.

         * (e.g. the bitmap is drawn, getPixels() is called), they will be

         * automatically re-decoded.

         *

         * For the re-decode to happen, the bitmap must have access to the

         * <p>For the re-decode to happen, the bitmap must have access to the

         * encoded data, either by sharing a reference to the input

         * or by making a copy of it. This distinction is controlled by

         * inInputShareable. If this is true, then the bitmap may keep a shallow

         * reference to the input. If this is false, then the bitmap will

         * explicitly make a copy of the input data, and keep that. Even if

         * sharing is allowed, the implementation may still decide to make a

         * deep copy of the input data.

         * deep copy of the input data.</p>

         *

         * <p>While inPurgeable can help avoid big Dalvik heap allocations (from

         * API level 11 onward), it sacrifices performance predictability since any

         * image that the view system tries to draw may incur a decode delay which

         * can lead to dropped frames. Therefore, most apps should avoid using

         * inPurgeable to allow for a fast and fluid UI. To minimize Dalvik heap

         * allocations use the {@link #inBitmap} flag instead.</p>

         *

         * <p class="note"><strong>Note:</strong> This flag is ignored when used

         * with {@link #decodeResource(Resources, int,

         * android.graphics.BitmapFactory.Options)} or {@link #decodeFile(String,

         * android.graphics.BitmapFactory.Options)}.</p>

         */

        public boolean inPurgeable;