Do not suspend CSS animations when page is hidden
[Title] Do not suspend CSS animations when page is hidden
[Issue#] TDIS-5549
[Problem] CSS animation gets suspended when moved to background.
[Cause] commit
f9d52256dc1509696c042ae7b7400fbaa271e8bd
was added to save CPU resource when page is hidden.
However, animated attributes are changed without it being
painted when page is in background, so almost no CPU resources
are used when css animation runs on a page that is hidden.
[Solution] revert previous patch
Change-Id: Idf54192a75709c2a6db1f755e9fb233b58eb2185