Simplify handler initialization for InputConnectionFactory

As a follow-up to https://codereview.chromium.org/2543893002/,
we make the code easy to read and remove unnecessary findbug suppression.

BUG=668692

Review-Url: https://codereview.chromium.org/2544163003
Cr-Commit-Position: refs/heads/master@{#436218}
2 files changed