Oilpan: implement StyleRuleList without an extra wrapper.

Source/core/editing/EditingStyle.cpp

Index: Source/core/editing/EditingStyle.cpp
diff --git a/Source/core/editing/EditingStyle.cpp b/Source/core/editing/EditingStyle.cpp
index 24bef043a64f95bcb58a5527559cbc2d1a8bd5b7..42b94139365b177e908a094d55b27b0c85663ac2 100644
--- a/Source/core/editing/EditingStyle.cpp
+++ b/Source/core/editing/EditingStyle.cpp
@@ -1167,8 +1167,8 @@ static PassRefPtrWillBeRawPtr<MutableStylePropertySet> styleFromMatchedRulesForE
     RefPtrWillBeRawPtr<MutableStylePropertySet> style = MutableStylePropertySet::create();
     RefPtrWillBeRawPtr<StyleRuleList> matchedRules = element->document().ensureStyleResolver().styleRulesForElement(element, rulesToInclude);
     if (matchedRules) {
-        for (unsigned i = 0; i < matchedRules->m_list.size(); ++i)
-            style->mergeAndOverrideOnConflict(&matchedRules->m_list[i]->properties());
+        for (unsigned i = 0; i < matchedRules->size(); ++i)
+            style->mergeAndOverrideOnConflict(&matchedRules->at(i)->properties());
     }
     return style.release();
 }