add pan-x and pan-y support to CSS touch-action parsing.

LayoutTests/fast/css/touch-action-parsing.html

Index: LayoutTests/fast/css/touch-action-parsing.html
diff --git a/LayoutTests/fast/css/touch-action-parsing.html b/LayoutTests/fast/css/touch-action-parsing.html
old mode 100644
new mode 100755
index 41037807204d837010682711a29330aafc73754b..b1b0fcedb526499184e2085c763803b3f0db0945
--- a/LayoutTests/fast/css/touch-action-parsing.html
+++ b/LayoutTests/fast/css/touch-action-parsing.html
@@ -17,8 +17,13 @@
 <div class="test" id="default" expected="auto"></div>
 <div class="test defnone" id="stylesheet-none" expected="none"></div>
 <div class="test defnone" id="explicit-auto" style="touch-action: auto;" expected="auto"></div>
+<div class="test defnone" id="explicit-pan-x" style="touch-action: pan-x;" expected="pan-x"></div>

[Rick Byers, 2013/12/06 21:44:04]

why use 'defnone' on these three tests?  I'd just remove it (like the
explicit-none below).  It's there to differentiate between 'auto' as an error
and 'auto' being explicitly applied.

[gnana, 2013/12/10 18:24:37]

Done.

+<div class="test defnone" id="explicit-pan-y" style="touch-action: pan-y;" expected="pan-y"></div>
+<div class="test defnone" id="explicit-pan-x-pan-y" style="touch-action: pan-x pan-y;" expected="pan-x pan-y"></div>

[Rick Byers, 2013/12/06 21:44:04]

it's probably worth adding 'pan-y pan-x'.  I'm guessing we'll flip the order
around, that's consistent with IE behavior (always lists pan-x before pan-y).

[gnana, 2013/12/10 18:24:37]

Done.

 <div class="test" id="explicit-none" style="touch-action: none;" expected="none"></div>
 <div class="test" id="explicit-invalid" style="touch-action: bogus;" expected="auto"></div>
+<div class="test" id="explicit-invalid" style="touch-action: auto pan-x;" expected="auto"></div>

[Rick Byers, 2013/12/06 21:44:04]

it's illegal to use the same ID more than once - please choose a unique name for
the test and the one below (invalid-2, invalid-3 etc. is fine, or something more
descriptive).

[Rick Byers, 2013/12/06 21:44:04]

Apply the 'defnone' class here and expect it to be 'none' to make it clear that
the whole rule is being rejected, not just the 'pan-x' token.

[gnana, 2013/12/10 18:24:37]

Done.

[gnana, 2013/12/10 18:24:37]

Done.

+<div class="test" id="explicit-invalid" style="touch-action: none pan-y;" expected="auto"></div>

[Rick Byers, 2013/12/06 21:44:04]

just for a bit more variety, I'd suggest 'pan-y none' instead of 'none pan-y'.

[gnana, 2013/12/10 18:24:37]

Done.

 <div style="touch-action: none;">
   <div class="test" id="not-inherited" expected="auto"></div>
   <div class="test" id="inherit" style="touch-action: inherit;" expected="none"></div>