rAc: set a couple colors after getting attached to a Widget.

Thus referencing the correct NativeTheme.

BUG=320899

Review URL: https://codereview.chromium.org/74423006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236413 0039d316-1c4b-4281-b951-d872f2087c98
Revert 235802 "PDFBrowserTest.Basic (see http://crbug.com/152330..."

Pawel fixed this in r236354 

> PDFBrowserTest.Basic (see http://crbug.com/152330), PDFBrowserTest.FindAndCopy and PDFBrowserTest.Scroll (see http://crbug.com/79837) are failing consistently on official Windows bot. Disabling it for now to keep official bot green.
> 
> BUG=152330, 79837
> 
> Review URL: https://codereview.chromium.org/67473008

TBR=pshenoy@chromium.org

Review URL: https://codereview.chromium.org/78983004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236414 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236414