SF: Updating video detection logic. This is V0.

- Remove timestamp detection for FPS, not needed
- Video is now detected via BufferItem.mApi ID
- Make sure Idle timer and media detection don't cancel
  each other.

see go/surface-flinger-scheduler for more info
see go/content-fps-detection-in-scheduler to see plans
for improvement.

Test: systrace
Bug: 123956502
Change-Id: I14390a3decd3da8fabf383bd3a2470864b027f7a