Camera2: Add onCaptureQueueEmpty callback

onCaptureQueueEmpty indicates that the non-repeating
capture request queue of camera device is empty, and
is ready to process a new request.

Test: testMultipleCapture in PerformanceTest.java

Bug: 29006447
Change-Id: If245ff6abf352548ca13a10fcfbd1550b92c1224
11 files changed