Revert r137630 (Source/WebCore: CanvasRenderingContext2D::setFont() is slow).

TBR=jamesr
BUG=

Review URL: https://codereview.chromium.org/19652009

git-svn-id: svn://svn.chromium.org/blink/trunk@154836 bbb929c8-8fbe-4397-9dbb-9b2b20218538