diff ./nsCSSDeclaration.h /Users/glazou/trees/xr-1905/mozilla/layout/style/nsCSSDeclaration.h
247a248,251
> 
>     // Block everyone, except us or a derivative, from deleting us.
>     ~nsCSSDeclaration(void);
>   
249,251d252
<   // Block everyone, except us or a derivative, from deleting us.
<   ~nsCSSDeclaration(void);
<     
diff ./nsCSSParser.cpp /Users/glazou/trees/xr-1905/mozilla/layout/style/nsCSSParser.cpp
204a205
>   void SkipUntilAtKeyword(nsresult& aErrorCode);
234a236,239
>   PRBool ParseIfImplementedRule(nsresult& aErrorCode);
>   PRBool ParseElseImplementedRule(nsresult& aErrorCode);
>   PRBool ParseEndifImplementedRule(nsresult& aErrorCode);
> 
478a484,486
>   PRPackedBool mHandlingCondition;
>   PRPackedBool mConditionValue;
> 
558c566,568
<     mParsingCompoundProperty(PR_FALSE)
---
>     mParsingCompoundProperty(PR_FALSE),
>     mHandlingCondition(PR_FALSE),
>     mConditionValue(PR_FALSE)
1278a1289,1303
>   if (mToken.mIdent.LowerCaseEqualsLiteral("if-implemented")) {
>     if (ParseIfImplementedRule(aErrorCode))
>       return PR_TRUE;
>   }
> 
>   if (mToken.mIdent.LowerCaseEqualsLiteral("else-implemented")) {
>     if (ParseElseImplementedRule(aErrorCode))
>       return PR_TRUE;
>   }
> 
>   if (mToken.mIdent.LowerCaseEqualsLiteral("endif-implemented")) {
>     if (ParseEndifImplementedRule(aErrorCode))
>       return PR_TRUE;
>   }
> 
1663a1689,1786
> PRBool CSSParserImpl::ParseIfImplementedRule(nsresult& aErrorCode)
> {
>   if (mHandlingCondition) {
>     // do not accept to nest @if-implemented rules
>     OUTPUT_ERROR();
>     return PR_FALSE;
>   }
> 
>   nsresult errorCode = NS_OK;
>   mHandlingCondition = PR_FALSE;
>   mConditionValue = PR_FALSE;
> 
>   if (!ExpectSymbol(aErrorCode, '{', PR_TRUE)) {
>     REPORT_UNEXPECTED_TOKEN(PEBadDeclBlockStart);
>     OUTPUT_ERROR();
>     return PR_FALSE;
>     }
>   UngetToken();
> 
>   nsCSSDeclaration* declaration = ParseDeclarationBlock(errorCode, PR_TRUE);
> 
>   mHandlingCondition = PR_TRUE;
>   if (declaration && declaration->Count()) {
>     delete declaration;
>     mConditionValue = PR_TRUE;
>   } else
>     mConditionValue = PR_FALSE;
> 
>   if (!mConditionValue) {
>     // condition is not met, skip until @else-implemented or @endif-implemented
>     for (;;) {
>       SkipUntilAtKeyword(aErrorCode);
>       if (!GetToken(aErrorCode, PR_FALSE)) {
>         return PR_FALSE;
>       }
>       if (eCSSToken_AtKeyword == mToken.mType) {
>         if (mToken.mIdent.LowerCaseEqualsLiteral("else-implemented") ||
>             mToken.mIdent.LowerCaseEqualsLiteral("endif-implemented")) {
>           UngetToken();
>           UngetToken();
>           return PR_TRUE;
>         }
>       }
>     }
>   }
> 
>   return PR_TRUE;
> }
> 
> PRBool CSSParserImpl::ParseElseImplementedRule(nsresult& aErrorCode)
> {
>   if (!mHandlingCondition) {
>     // we must have had a @if-implemented before...
>     OUTPUT_ERROR();
>     return PR_FALSE;
>   }
> 
>   if (!ExpectSymbol(aErrorCode, ';', PR_TRUE)) {
>     return PR_FALSE;
>   }
> 
>   if (mConditionValue) {
>     // condition is met, skip until @else-implemented or @endif-implemented
>     for (;;) {
>       SkipUntilAtKeyword(aErrorCode);
>       if (!GetToken(aErrorCode, PR_FALSE)) {
>         return PR_FALSE;
>       }
>       if (eCSSToken_AtKeyword == mToken.mType) {
>         if (mToken.mIdent.LowerCaseEqualsLiteral("endif-implemented")) {
>           UngetToken();
>           UngetToken();
>           return PR_TRUE;
>         }
>       }
>     }
>   }
> 
>   return PR_TRUE;
> }
> 
> PRBool CSSParserImpl::ParseEndifImplementedRule(nsresult& aErrorCode)
> {
>   if (!mHandlingCondition) {
>     // we must have had a @if-implemented before...
>     OUTPUT_ERROR();
>     return PR_FALSE;
>   }
> 
>   if (!ExpectSymbol(aErrorCode, ';', PR_TRUE)) {
>     return PR_FALSE;
>   }
> 
>   mHandlingCondition = PR_FALSE;
> 
>   return PR_TRUE;
> }
> 
1685a1809,1832
> void CSSParserImpl::SkipUntilAtKeyword(nsresult& aErrorCode)
> {
>   nsCSSToken* tk = &mToken;
>   for (;;) {
>     if (!GetToken(aErrorCode, PR_TRUE))
>       return;
> 
>     if (eCSSToken_AtKeyword == tk->mType)
>     {
>       UngetToken();
>       return;
>     } else if (eCSSToken_Symbol == tk->mType) {
>       PRUnichar symbol = tk->mSymbol;
>       if ('{' == symbol) {
>         SkipUntil(aErrorCode, '}');
>       } else if ('[' == symbol) {
>         SkipUntil(aErrorCode, ']');
>       } else if ('(' == symbol) {
>         SkipUntil(aErrorCode, ')');
>       }
>     }
>   }
> }
>