Remove BackoffEntry TODO that was wrong.
Remove BackoffEntry TODO that was wrong.

Clarify comment to illustrate why the current behavior is correct.

BUG=None

Review URL: https://chromiumcodereview.appspot.com/9773032

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@129177 0039d316-1c4b-4281-b951-d872f2087c98

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