tree 57fcadbe3ee6a1f0d7b656cbb51bfc400b9554a3
parent cd50a0fade590098b4322140c5fede04c6e7eb8e
author Tony Wickham <twickham@google.com> 1456340820 -0800
committer Tony Wickham <twickham@google.com> 1457139174 -0800

Pinch to zoom out into overview mode.

There are 3 classes coordinating the gesture: PinchToOverviewListener,
PinchThresholdManager, and PinchAnimationManager.
- PTOL listens for the pinch gesture on DragLayer.
- When a pinch is detected, the PTOL keeps track of the interpolated
  progress and passes it along to both the PTM and PAM.
- The PTM uses the progress to determine whether a new threshold has
  been passed, and tells the PAM to animate it if so.
- The PAM uses the progress to animate things like workspace scale
  throughout the pinch.
- If the pinch ends early, the PTOL uses the last passed threshold to
  determine whether to animate to workspace or overview, and tells
  PAM to perform the animation at the same velocity as the pinch.

Bug: 24414635
Change-Id: I9e53706c705f8b2982409bf7c223d8d0e9618bf0