DevTools: [DefaultTextEditor] kill DefaultTextEditor

This patch:
- Removes DefaultTextEditor code from the source-code
- Removes unused classes from textEditor.css
- Additionally adds a 'position:relative' rule for CodeMirrorTextEditor
element. This makes it possible to set up a fixed height in
editor-test.js

BUG=

Review URL: https://chromiumcodereview.appspot.com/19723007

git-svn-id: svn://svn.chromium.org/blink/trunk@154577 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Expose atob() / btoa() to workers

Expose atob() / btoa() to workers as per the latest Web Workers
specification:
http://www.whatwg.org/specs/web-apps/current-work/multipage/workers.html#WorkerGlobalScope-partial
http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#windowbase64

This behavior is consistent with Firefox and IE10.

BUG=143502
R=arv@chromium.org, haraken@chromium.org

Review URL: https://codereview.chromium.org/19749003

git-svn-id: svn://svn.chromium.org/blink/trunk@154578 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Drop [LegacyImplementedInBaseClass] attribute from WindowTimers

Drop [LegacyImplementedInBaseClass] IDL extended attribute from the
WindowTimers interface and move the code to a new DOMWindowTimers
file to reduce code duplication.

There is still some duplication in the custom bindings code but this
will be addressed in a later patch to limit patch size.

R=arv@chromium.org, haraken@chromium.org

Review URL: https://codereview.chromium.org/19801002

git-svn-id: svn://svn.chromium.org/blink/trunk@154579 bbb929c8-8fbe-4397-9dbb-9b2b20218538