replace deprecated SkScalarRound/Floor/Ceil calls with more explicit variants

BUG=

Review URL: https://codereview.chromium.org/122443005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243175 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243175