Set upper limit of process queue in MainContentCaptureSessionV2

To prevent view events starting accumulated in the process queue, an
upper limit must be provided. This should address a potential memory
usage issue when no FORCE_FLUSH signal is presented for a while.

Test: MainContentCaptureSessionV2, CtsContentCaptureServiceTestCases
Bug: 309411951

Change-Id: I9054cdfb50212550a87b5e52b7706462a53e97fe
2 files changed