31b68fe639
* add a real proper pointer for holding memory chunk pointer (instead of using y and argb fields) * polish the doc with details * add a WebPPictureView() that extract a view from a picture without any copy (kind of a fast-crop). * properly snap the top-left corner for Crop/View. Previously, the luma position was not snapped, and was off compared to the chroma. Change-Id: I8a3620c7f5fc6f7d1f8dd89d9da167c91e237439