Implementation of CSS3 nav-up/down/left/right properties from CSS3 UI.

Source/core/css/CSSProperties.in

Index: Source/core/css/CSSProperties.in
diff --git a/Source/core/css/CSSProperties.in b/Source/core/css/CSSProperties.in
index 3f9c61e8957f37ad9bc46eff0531d5136c3a8495..85334e9c6d7ecb82b7401bcec9b2230815faddbd 100644
--- a/Source/core/css/CSSProperties.in
+++ b/Source/core/css/CSSProperties.in
@@ -212,6 +212,10 @@ max-width animatable, initial=initialMaxSize, converter=convertLengthMaxSizing
 min-height animatable, initial=initialMinSize, converter=convertLengthSizing
 min-width animatable, initial=initialMinSize, converter=convertLengthSizing
 mix-blend-mode runtime_flag=CSSCompositing, type_name=blink::WebBlendMode, name_for_methods=BlendMode
+nav-down type_name=StyleNavigationValue, initial=initialStyleNavigation, converter=convertStyleNavigationValue

[fs, 2014/10/01 10:52:14]

Might want to consider adding a runtime feature for these properties (in
addition to the setting...) to prevent exposing these even when will not
actually work - for things like @supports(nav-...) etc. (Read: I'm not sure if
other users of Chromium will be happy about exposing these properties.)

+nav-left type_name=StyleNavigationValue, initial=initialStyleNavigation, converter=convertStyleNavigationValue
+nav-right type_name=StyleNavigationValue, initial=initialStyleNavigation, converter=convertStyleNavigationValue
+nav-up type_name=StyleNavigationValue, initial=initialStyleNavigation, converter=convertStyleNavigationValue
 object-fit type_name=ObjectFit
 object-position animatable, converter=convertLengthPoint
 opacity animatable, type_name=float