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

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235802 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235802