To reproduce: 1. Launch Safari 2. Go to data:text/html,<button>test 3. Open a new tab 4. Go to data:text/html,<button>test In step 2, a Mac-style button is drawn. In step 4, a Windows-style button is drawn. This regressed in r44758 <http://trac.webkit.org/changeset/44758>.
<rdar://problem/6981976>
The problem is that RenderTheme::themeForPage is getting called before WebPreferences has communicated its settings to WebCore::Settings. RenderTheme::themeForPage consults Settings to decide whether it should return the RenderThemeWin or RenderThemeSafari instance, but Settings hasn't been initialized yet.
Created attachment 31441 [details] patch v1 + ChangeLog
Comment on attachment 31441 [details] patch v1 + ChangeLog r=me I'm sad we have to work around this instead of fixing it. Too bad we didn't realize this was wrong before landing the per-page theme change!
Comment on attachment 31441 [details] patch v1 + ChangeLog r=me
Fixed in r44785
I've recorded the desire to fix the real bug in bug 26494.