Refactoring: Make IPC::Channel::TakeClientFileDescriptor() a ScopedFD.

By using base::ScopedFD, the ownership of the returned FD becomes
clearer.

BUG=415294
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Review URL: https://codereview.chromium.org/621613002

Cr-Commit-Position: refs/heads/master@{#300381}
38 files changed