RenderTextControl.cpp hard-codes scrollbar size to 15 pixels the comments say that this should use RenderTheme instead. after discussing with maciej on #webkit, it seems like the best solution is a method on RenderTheme that takes a RenderObject parameter so that the scrollbar size can vary (e.g., on OS X, mini controls have a smaller scrollbar).
Created attachment 14874 [details] simple patch I went with the simpler version of the patch since other code in rendering/ invokes PlatformScrollbar::horizontalScrollbarHeight()/verticalScrollbarWidth() Moreover, this ends up not being a real code change since it's just replacing a hard-coded 15 with a static function that returns 15 (on Mac).
Comment on attachment 14874 [details] simple patch r=me
Landed in r22017.