GitLab

Original attempt CL:1888652 got reverted because a new usage popped up.

HomeLauncherGestureHandler currently has three observers:
1.  AppListControllerImpl, which is also a HomeScreenDelegate
    implementation (on which HomeScreenGestureHandler already
    depends, so additional observer interface just
    obscures/complicates this dependency)
2.  HomeLauncherStateWaiter which is used by interactive UI/perf tests
    to wait for launcher animations to complete
3.  BackdropController which pauses backdrop updates while home launcher
    drag is in progress
    (this landed in parallel with first attempt of landing this)

For case 1., moving the observer methods to HomeScreenDelegate
interface will work fine.

For case 2., the test waiter can register a callback with
AppListControllerImpl to be run when the home launcher animations are
complete - the same way it's done by LauncherStateWaiter, an equivalent
test waiter used in clamshell mode (or for waiting for non-visibility
app list state transitions)

For case 3. the dependency is switched - instead of BackdropController
observering HomeLauncherGestureHandler for drag events,
HomeLauncherGestureHandler requests pause in backdrop updates while home
launcher state transitions are in progress. Given that
HomeLauncherGestureHandler already depends in BackdropController (to
animate backdrop window), this removes newly added circular dependency.

BUG=1005366

Change-Id: I73e249eaf41d8ccf1e349dfa6ba023eccb97159a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894464Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712224}