result = GetContext(aPresContext, aParentContext, nsnull);
result = GetContext(aPresContext, aParentContext, nsnull).get();
nsIStyleContext* StyleSetImpl::ResolveStyleFor(nsIPresContext* aPresContext,                                               nsIContent* aContent,                                               nsIStyleContext* aParentContext){  MOZ_TIMER_DEBUGLOG(("Start: StyleSetImpl::ResolveStyleFor(), this=%p\n", this));  STYLESET_START_TIMER(NS_TIMER_STYLE_RESOLUTION);  nsIStyleContext*  result = nsnull;  NS_ASSERTION(aContent, "must have content");  NS_ASSERTION(aPresContext, "must have pres context");  NS_ASSERTION(aContent->IsContentOfType(nsIContent::eELEMENT),               "content must be element");  if (aContent && aPresContext) {    GatherRuleProcessors();    if (mAgentRuleProcessors ||        mUserRuleProcessors  ||        mDocRuleProcessors   ||        mOverrideRuleProcessors) {      EnsureRuleWalker(aPresContext);      nsCOMPtr<nsIAtom> medium;      aPresContext->GetMedium(getter_AddRefs(medium));      RulesMatchingData data(aPresContext, medium, aContent, mRuleWalker);      FileRules(EnumRulesMatching, &data);      result = GetContext(aPresContext, aParentContext, nsnull);           // Now reset the walker back to the root of the tree.      mRuleWalker->Reset();    }  }  MOZ_TIMER_DEBUGLOG(("Stop: StyleSetImpl::ResolveStyleFor(), this=%p\n", this));  STYLESET_STOP_TIMER(NS_TIMER_STYLE_RESOLUTION);  return result;}