Update the opacity of app list background and all the items in the app list during dragging fullscreen app list from the shelf.
1) Only tablet mode. Swiping up on the shelf to open the fullscreen app list.
2) Update the background opacity of app list based on the shelf's original opacity. Changes gradually to its final opacity (0.8 currently). The relationship,
Applist background opacity = (Opacity of app list) * t + (1 - t) * (opacity of shelf)
t = gesture_drag_amount / (3.0 * shelfsize)
"3.0" here because the shelf is visible, should subtract this one's size.
3) Update opacity of all the items in the app list, includes,
searchbox view,
suggested_indicator,
suggested_apps,
all_apps_indicator,
all apps in the first page(since will only show the first page during dragging).
page switcher if one exists
The opacity of the items changes gradually to its final opacity (1.0).
Formula of the current opacity,
Opacity of item = (work_area_bottom - centroid of the item's bounds in screen) / (2.0 * shelfsize)
Comment 1 by minch@chromium.org
, Jul 25 2017