Revert 168553 "id of iframe incorrectly sets window name"

This CL might broke browser_tests in Mac:
http://build.chromium.org/p/chromium.webkit/builders/Mac10.8%20Tests/builds/6374

> id of iframe incorrectly sets window name
> 
> As per the specification, the iframe's name should be an empty string if unset:
> http://www.whatwg.org/specs/web-apps/current-work/multipage/the-iframe-element.html#attr-iframe-name
> 
> Instead, Chromium was using the iframe's id as window name if the name was
> unset. This change makes us behave like Firefox 27 and IE 11, verified using:
> http://jsfiddle.net/xf5H7/9/
> 
> This CL sets the name attribute iframe in a lot of layout tests so that
> testRunner.dumpChildFramesAsText() keeps printing the same result.
> 
> R=arv@chromium.org, tkent@chromium.org, abarth, arv, tkent
> BUG=347169
> TEST=fast/frames/iframe-no-name.html
> 
> Review URL: https://codereview.chromium.org/187103002

TBR=ch.dumez@samsung.com

Review URL: https://codereview.chromium.org/184633004

git-svn-id: svn://svn.chromium.org/blink/trunk@168579 bbb929c8-8fbe-4397-9dbb-9b2b20218538