Fixed the clang warning for ApmDataDumper

BUG=

Review-Url: https://codereview.webrtc.org/2296693002
Cr-Original-Commit-Position: refs/heads/master@{#13975}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: f8f754a1a6d2aa437856edc7ae90d47c9b2b0ccd
2 files changed