Implement touch-action pan-x/pan-y handling on the main thread

Source/web/tests/data/touch-action-simple.html

Index: Source/web/tests/data/touch-action-simple.html
diff --git a/Source/web/tests/data/touch-action-simple.html b/Source/web/tests/data/touch-action-simple.html
old mode 100644
new mode 100755
index 6219b147008ad7de17dff79be53457787c23a809..436e744371457cd6ea5d3628953e17b67c9680ba
--- a/Source/web/tests/data/touch-action-simple.html
+++ b/Source/web/tests/data/touch-action-simple.html
@@ -8,6 +8,9 @@
 
 <div expected-action='auto'>Simple div with no explicit touch-action</div>
 <div class='ta-none' expected-action='none'>Simple div with touch-action: none</div>
+<div class='ta-panx' expected-action='pan-x'>Simple div with touch-action: pan-x</div>

[Rick Byers, 2013/12/12 20:47:24]

Please add a separate test case / input file for the pan cases.  These are no
longer really "simple" and breaking it up makes it easier to prioritize and
debug failures.

I don't have a strong opinion about the overflow scroll cases - they could
either stay in the scroll test case or move to the pan test case.

[gnana, 2013/12/13 16:52:53]

Done.

+<div class='ta-pany' expected-action='pan-y'>Simple div with touch-action: pan-y</div>
+<div class='ta-panxy' expected-action='pan-x pan-y'>Simple div with touch-action: pan-x pan-y</div>
 
 <div class='ta-none' style='height: 0; margin-bottom: 50px'>
   <div expected-action='none'>
@@ -21,6 +24,48 @@
   </div>
 </div>
 
+<div class='ta-none' style='height: 0; margin-bottom: 50px'>
+  <div class='ta-panx' expected-action='none'>
+    Explicitly setting touch-action: pan-x does nothing to prevent propagation of none
+  </div>
+</div>
+
+<div class='ta-none' style='height: 0; margin-bottom: 50px'>
+  <div class='ta-pany' expected-action='none'>
+    Explicitly setting touch-action: pan-y does nothing to prevent propagation of none

[Rick Byers, 2013/12/12 20:47:24]

It's probably overkill to list each possible combination here, but we should try
to hit some of the key different branches in the code (most of which aren't
covered here).  So I'd suggest maybe:
 - outer=ta-none, inner=ta-panx (as you have above)
 - outer=ta-pany, inner=none
 - outer=ta-panx, inner=ta-pany (as you have below)
 - outer=ta-panxy, inner=ta-auto
 - outer=ta-panx, inner=ta-panxy
 - outer=ta-panxy, inner=ta-pany
 - maybe one 3-level case, like outer=ta-panx middle=ta-auto inner=ta-pany

[gnana, 2013/12/13 16:52:53]

Done.

+  </div>
+</div>
+
+<div class='ta-none' style='height: 0; margin-bottom: 50px'>
+  <div class='ta-panxy' expected-action='none'>
+    Explicitly setting touch-action: pan-x pan-y does nothing to prevent propagation of none
+  </div>
+</div>
+
+<div class='ta-panx' style='height: 0; margin-bottom: 50px'>

[Rick Byers, 2013/12/12 20:47:24]

You don't need the 'height:- margin-bottom: 50px' hack in this case.  The point
of that hack is to ensure that a hit-testing bug that picked up the outer
element instead of the inner one wouldn't produce the same result as what we
expect.  In this case (and many of the other ones I suggested above) the
expected action is different from that of the outer div, so they can just have a
normal containment relationship without risking any such bug.

[gnana, 2013/12/13 16:52:53]

Done.

+  <div class='ta-pany' expected-action='none'>
+    Explicitly setting touch-action: pan-y does nothing to prevent propagation of pan-x resulting to none

[Rick Byers, 2013/12/12 20:47:24]

I don't think the 'prevent propagation of...' part of the description still
applies to this case.  I'd simplify the description of this test to something
like "Disjoint flags intersect to none".

[gnana, 2013/12/13 16:52:53]

Done.

+  </div>
+</div>
+
+<div class='ta-pany' style='height: 0; margin-bottom: 50px'>
+  <div class='ta-panx' expected-action='none'>
+    Explicitly setting touch-action: pan-x does nothing to prevent propagation of pan-y resulting to none
+  </div>
+</div>
+
+<div class='ta-panx' style='height: 0; margin-bottom: 50px'>
+  <div class='ta-panxy' expected-action='pan-x'>
+    Explicitly setting touch-action: pan-x pan-y does nothing to prevent propagation of pan-x
+  </div>
+</div>
+
+<div class='ta-pany' style='height: 0; margin-bottom: 50px'>
+  <div class='ta-panxy' expected-action='pan-y'>
+    Explicitly setting touch-action: pan-x pan-y does nothing to prevent propagation of pan-y
+  </div>
+</div>
+
 <div style='padding: 20px 0'>
   <span class='ta-none' expected-action='auto'>Touch-action should be ignored on inline elements
     <div expected-action='auto'>And not propagated to any block children</div>