Make chrome/ be documentElement/body agnostic with regards to scrollTop/Left

Blink is in the process of getting itself in pair with how other Web engines'
(Trident,Gecko,Presto) behavior with regards to scrollTop and scrollLeft when
called for documentElement and body. This process has been proved itself
to be of great impact within Chrome, given that its UI is written in HTML/JS/CSS.
See for example bugs 305800, 304753, 305745, 304816, 305742, 305092.

This CL tries to prevent Chrome from future similar breakages, as the Blink process
of adapting to this change is not yet 100% finalized. It will also allow CLs 69143002 and 51553002  to land without breaking Chrome.

CL also fixes driven-by issues like the usage of getElementById instead of $, so CQ can land the CL.

Additionally, a PRESUBMIT hook is being considered as well, in order to
advice programmers to not user {documentElement.body}.scroll{Top,Left} directly
and instead use the helper added to resources/js/util.js


Review URL:

git-svn-id: svn:// 0039d316-1c4b-4281-b951-d872f2087c98
9 files changed