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

Source/core/css/CSSComputedStyleDeclaration.cpp

Index: Source/core/css/CSSComputedStyleDeclaration.cpp
diff --git a/Source/core/css/CSSComputedStyleDeclaration.cpp b/Source/core/css/CSSComputedStyleDeclaration.cpp
old mode 100644
new mode 100755
index 82d0c741688d8cd2ba4159284ff508c06120f53c..671a0bf84c9e9456b2e34f2cd54f34747086cda4
--- a/Source/core/css/CSSComputedStyleDeclaration.cpp
+++ b/Source/core/css/CSSComputedStyleDeclaration.cpp
@@ -1542,6 +1542,23 @@ static PassRefPtr<CSSPrimitiveValue> valueForFontWeight(RenderStyle& style)
     return cssValuePool().createIdentifierValue(CSSValueNormal);
 }
 
+static PassRefPtr<CSSValue> touchActionFlagsToCSSValue(int touchAction)

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

This should take a TouchAction.   You could always add an operator& to
TouchAction (along with your operator|) if you like.

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

Done.

+{
+    RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+    if (touchAction & TouchActionNone)
+        list->append(cssValuePool().createIdentifierValue(CSSValueNone));
+    if (touchAction & TouchActionAuto)
+        list->append(cssValuePool().createIdentifierValue(CSSValueAuto));
+    if (touchAction & TouchActionPanX)

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

We should probably ASSERT or otherwise reject the invalid combinations here (so
we're sure we never produce a value list that would fail to parse) - including
an empty list. 

Is there precedent for similar invalid value handling elsewhere? 

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

I m checking on this. i will update this in next patch.

[Rick Byers, 2013/12/10 21:57:14]

Ok.  Whatever the common error-handling pattern seems to be is fine with me - it
seems like it should be pretty unlikely for this to ever be an issue.

[gnana, 2013/12/11 14:02:53]

Done.

+        list->append(cssValuePool().createIdentifierValue(CSSValuePanX));
+    if (touchAction & TouchActionPanY)
+        list->append(cssValuePool().createIdentifierValue(CSSValuePanY));
+
+    if (!list->length())
+        return cssValuePool().createIdentifierValue(CSSValueAuto);
+    return list.release();
+}
+
 static bool isLayoutDependent(CSSPropertyID propertyID, PassRefPtr<RenderStyle> style, RenderObject* renderer)
 {
     // Some properties only depend on layout in certain conditions which
@@ -2316,7 +2333,7 @@ PassRefPtr<CSSValue> CSSComputedStyleDeclaration::getPropertyCSSValue(CSSPropert
         case CSSPropertyTop:
             return valueForPositionOffset(*style, CSSPropertyTop, renderer, m_node->document().renderView());
         case CSSPropertyTouchAction:
-            return cssValuePool().createValue(style->touchAction());
+            return touchActionFlagsToCSSValue(style->touchAction());
         case CSSPropertyTouchActionDelay:
             return cssValuePool().createValue(style->touchActionDelay());
         case CSSPropertyUnicodeBidi: