Use std::shared_ptr in Epoll's callback list.

Ignore-AOSP-First: Awaiting security triage
Bug: 187862380
Bug: 184569329
Test: CtsInitTestCases
Change-Id: Ibb34a6b8a5675dbc515b7f8a43d7eecf2084510c
(cherry picked from commit aea97815308ab98faf1599c16d6190b787d34941)
(cherry picked from commit 2cf268ab9fd5c4ac6ac4ce7d2ecead212f019fc0)
4 files changed