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..6b38d9fcf5bf82b363e003d4383082f4de33c172
--- 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(TouchAction touchAction)
+{
+    RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+    if (touchAction & TouchActionNone)
+        list->append(cssValuePool().createIdentifierValue(CSSValueNone));
+    if (touchAction & TouchActionAuto)
+        list->append(cssValuePool().createIdentifierValue(CSSValueAuto));
+    if (touchAction & TouchActionPanX)
+        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: