Simplify watched selector handling and remove remnants of user stylesheets

Source/core/dom/CSSSelectorWatch.cpp

Index: Source/core/dom/CSSSelectorWatch.cpp
diff --git a/Source/core/dom/CSSSelectorWatch.cpp b/Source/core/dom/CSSSelectorWatch.cpp
index 8fa8255ec8e611adb515c1ef2ef885c3fe437e8c..7df0db91e100e328b99ccc218586b836d7f657d3 100644
--- a/Source/core/dom/CSSSelectorWatch.cpp
+++ b/Source/core/dom/CSSSelectorWatch.cpp
@@ -143,7 +143,9 @@ void CSSSelectorWatch::watchCSSSelectors(const Vector<String>& selectors)
     m_watchedCallbackSelectors.clear();
     BisonCSSParser parser(CSSParserContext(UASheetMode, 0));
 
-    const CSSProperty callbackProperty(CSSPropertyInternalCallback, CSSPrimitiveValue::createIdentifier(CSSValueInternalPresence));
+    // We need a property declaration here otherwise the StylePropertySet will
+    // get ignored. The exact property used doesn't matter as it isn't applied.
+    const CSSProperty callbackProperty(CSSPropertyBackgroundColor, CSSPrimitiveValue::createIdentifier(CSSValueRed));

[esprehn, 2014/08/15 14:45:55]

This hack feels pretty gross, we can't leave that old property?

[Timothy Loh, 2014/08/15 15:29:14]

Turns out there's a flag on MatchRequest to make us not ignore empty
StylePropertySets, so we don't need a property here any more.

     const RefPtrWillBeRawPtr<StylePropertySet> callbackPropertySet = ImmutableStylePropertySet::create(&callbackProperty, 1, UASheetMode);
 
     CSSSelectorList selectorList;