Content Shell: Drop an unused method.

Content Shell: Drop an unused method.

ShellDevToolsFrontend::RenderProcessGone's functionality is now entirely
contained in LayoutTestDevToolsFrontend; I should have removed this
definition in https://codereview.chromium.org/644723002.

BUG=420994
Committed: https://crrev.com/781ceef3f7da81f3b9567d8b173172742c6b8140
Cr-Commit-Position: refs/heads/master@{#299081}

[Mike West, 2014-10-10 08:21:52]

mkwst@chromium.org changed reviewers:
+ peter@chromium.org

[Mike West, 2014-10-10 08:21:53]

WDYT, Peter?

[pfeldman, 2014-10-10 08:35:52]

pfeldman@chromium.org changed reviewers:
+ pfeldman@chromium.org

[pfeldman, 2014-10-10 08:35:53]

lgtm.

[Mike West, 2014-10-10 08:36:22]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2014-10-10 08:37:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/644963002/140001

[commit-bot: I haz the power, 2014-10-10 09:04:23]

Committed patchset #3 (id:140001)

[commit-bot: I haz the power, 2014-10-10 09:05:08]

Patchset 3 (id:??) landed as
https://crrev.com/781ceef3f7da81f3b9567d8b173172742c6b8140
Cr-Commit-Position: refs/heads/master@{#299081}