DevTools: always use CodeMirror for response preview

DevTools: always use CodeMirror for response preview

Currently, the response preview of Network Panel uses CodeMirror for
contents less then ~100Kb and fallbacks to a simple DIV with
word-wrapped text otherwise. The DIV with word-wrapped text might be
very slow to render.

The fallback was implemented in crrev.com/14432002 to avoid text
truncation bug in codeMirror: crbug.com/168052. Nowadays, the bug does
not seem to be reproducible in CodeMirror any more, so it is safe to
use CodeMirror all the time.

BUG=519131
R=pfeldman

Committed: https://crrev.com/bcbae5e5ff246b578c4cd03bb8ded107a60cd3db
Cr-Commit-Position: refs/heads/master@{#356981}

[lushnikov, 2015-10-29 20:52:50]

ptal

[lushnikov, 2015-10-29 20:52:59]

The CQ bit was checked by lushnikov@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-10-29 20:54:10]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1419813005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1419813005/1

[pfeldman, 2015-10-29 22:31:00]

lgtm

[commit-bot: I haz the power, 2015-10-29 23:02:06]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-10-29 23:02:07]

Dry run: This issue passed the CQ dry run.

[lushnikov, 2015-10-29 23:03:21]

The CQ bit was checked by lushnikov@chromium.org

[commit-bot: I haz the power, 2015-10-29 23:07:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1419813005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1419813005/1

[commit-bot: I haz the power, 2015-10-29 23:31:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-29 23:32:04]

Patchset 1 (id:??) landed as
https://crrev.com/bcbae5e5ff246b578c4cd03bb8ded107a60cd3db
Cr-Commit-Position: refs/heads/master@{#356981}