add 'manipulation' 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
index 12179899c4d5ed218ec3718d3c6c781f14a28f8b..eafceed820d241ee5506c81950ea64d4896e4bb8 100644
--- a/Source/core/css/CSSComputedStyleDeclaration.cpp
+++ b/Source/core/css/CSSComputedStyleDeclaration.cpp
@@ -1439,11 +1439,12 @@ static PassRefPtrWillBeRawPtr<CSSValue> touchActionFlagsToCSSValue(TouchAction t
         ASSERT(touchAction == TouchActionNone);
         list->append(cssValuePool().createIdentifierValue(CSSValueNone));
     }
-    if (touchAction & TouchActionPanX)
+    if (!(touchAction & TouchActionZoom) && (touchAction & TouchActionPanX))
         list->append(cssValuePool().createIdentifierValue(CSSValuePanX));
-    if (touchAction & TouchActionPanY)
+    if (!(touchAction & TouchActionZoom) && (touchAction & TouchActionPanY))
         list->append(cssValuePool().createIdentifierValue(CSSValuePanY));
-
+    if (touchAction & TouchActionZoom)

[Rick Byers, 2014/03/05 14:41:13]

This code should ASSERT on invalid combinations like 'TouchActionZoom' on it's
own (rather than silently converting it to 'manipulation').

Perhaps put 'if (touchAction == TouchActionZoom | TouchActionPanX |
TouchActionPanY)' first and put the remaining PanX/PanY cases inside an else
block?

[gnana, 2014/03/06 08:11:14]

Done.

+        list->append(cssValuePool().createIdentifierValue(CSSValueManipulation));
     ASSERT(list->length());
     return list.release();
 }