.: Added manual test for canvas setFont speed.

.: Added manual test for canvas setFont speed.
https://bugs.webkit.org/show_bug.cgi?id=104923

Reviewed by James Robinson.

* ManualTests/canvas-font-speed.html: Added.

Source/WebCore: CanvasRenderingContext2D::setFont() is slow.
https://bugs.webkit.org/show_bug.cgi?id=104923

Reviewed by James Robinson.

This spends most of its time in the CSS parser.  As a first step,
early-out if the new value is the same as unparsed string for the current font.
See also http://code.google.com/p/chromium/issues/detail?id=164016.

Covered by existing tests in canvas/ and fast/canvas, and ManualTests/canvas-font-speed.html.

* html/canvas/CanvasRenderingContext2D.cpp:
(WebCore::CanvasRenderingContext2D::setFont):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@137630 268f45cc-cd09-0410-ab3c-d52691b4dbfc