Bug 966992 - Add a CSS_PROPERTY_ALWAYS_ENABLED_IN_UA_SHEETS bit for properties that are enabled by a pref but that are always enabled in UA sheets.  r=cam  a=sledru
Bug 966992 - Implement the overflow-clip-box property in the style system.  r=cam  a=sledru
Bug 966992 - Implement layout for the overflow-clip-box property.  r=roc  a=sledru
Bug 965237 - Make overflow-clip-box:content-box be the default for <input type=text/password/number> and <textarea>.  r=roc  a=sledru
Bug 966992 - overflow-clip-box:content-box tests.  a=sledru