Rename Looper::isIdling() to isPolling() to resolve confusion.

The loop isn't technically idle at this time, it's just checking
whether any file descriptors have pending events.  However it's
still a good signal as to whether the loop is alive.

Bug: 19532373
Change-Id: I555c473e70ffd8a56e1b10aa60026eb674a16de9
2 files changed