Bailing out if pc factory fails to get created.
Bailing out if pc factory fails to get created.

This prevents us from continuing if we fail initialization.
The failure will happen closer to its source, rather than
when we try to create the first peer connection.

BUG=None
R=glaznev@webrtc.org

Review URL: https://codereview.webrtc.org/1339923004 .

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#9948}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 6eb75d9e67f02c256436eb96f3c77026486561a1

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