Web Inspector: fix highlight bug in DTE.

Web Inspector: fix highlight bug in DTE.
https://bugs.webkit.org/show_bug.cgi?id=107433

Patch by Andrey Lushnikov <lushnikov@chromium.org> on 2013-01-21
Reviewed by Pavel Feldman.

Source/WebCore:

Do not re-create |state.ranges| array when it already contains highlight.

Test: inpector/editor/highlighter-chunk-limit.txt

* inspector/front-end/TextEditorHighlighter.js:
(WebInspector.TextEditorHighlighter.prototype._highlightLines):

LayoutTests:

Add a layout test to cover highlight bug specific situation.

* inspector/editor/highlighter-chunk-limit-expected.txt: Added.
* inspector/editor/highlighter-chunk-limit.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@140320 268f45cc-cd09-0410-ab3c-d52691b4dbfc