Use variadic templates instead of pump for RefCountedObject

BUG=None

Review-Url: https://codereview.webrtc.org/2438013003
Cr-Original-Commit-Position: refs/heads/master@{#14714}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 97abf244ca148bb0d8bb5d2eb235f6d1cd99a958
2 files changed