Fix RawChannelIOHandler leak on shutdown which is tripping the handle verifier.
Fix RawChannelIOHandler leak on shutdown which is tripping the handle verifier.

BUG=574325

Review URL: https://codereview.chromium.org/1583393005

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#369817}

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