DevTools: [CodeMirror] increase LongLinesMode threshold up to 2000

This patch improves LongLinesMode threshold up to 2000 as it is
somewhat likely to find a single 1000-chars long line in a regular
source code.

BUG=
TBR=pfeldman

Review URL: https://codereview.chromium.org/18069002

git-svn-id: svn://svn.chromium.org/blink/trunk@153138 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Refine expectation for a blink test flaking on Win7 on the V8 waterfall.

See http://test-results.appspot.com/dashboards/flakiness_dashboard.html#group=%40ToT%20V8&tests=http/tests/w3c/webperf/submission/Google/HighResolutionTime/worker-dedicated-basic.html

Review URL: https://chromiumcodereview.appspot.com/18019002

git-svn-id: svn://svn.chromium.org/blink/trunk@153139 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: [CodeMirror] Improve tab behaviour in CodeMirrorTextEditor

This patch changes the tab behaviour so that it indents to the nearest
column which number is devisible by indent amount without reminder.

BUG=
R=vsevik@chromium.org

Review URL: https://codereview.chromium.org/18059004

git-svn-id: svn://svn.chromium.org/blink/trunk@153140 bbb929c8-8fbe-4397-9dbb-9b2b20218538