Bug 1224121 - change getRelativeRuleLine to return 0 for line-less rules; r=heycam

layout/inspector/inDOMUtils.cpp

@@ -318,7 +318,7 @@ inDOMUtils::GetRelativeRuleLine(nsIDOMCSSRule* aRule, uint32_t* _retval)
 
   uint32_t lineNumber = rule->GetLineNumber();
   CSSStyleSheet* sheet = rule->GetStyleSheet();
-  if (sheet) {
+  if (sheet && lineNumber != 0) {
     nsINode* owningNode = sheet->GetOwnerNode();
     if (owningNode) {
       nsCOMPtr<nsIStyleSheetLinkingElement> link =

layout/inspector/tests/test_getRelativeRuleLine.html

@@ -34,10 +34,12 @@
     { sheetNo: 1, ruleNo: 0, lineNo: 2, columnNo: 15 },
     { sheetNo: 1, ruleNo: 1, lineNo: 8, columnNo: 5 },
     { sheetNo: 2, ruleNo: 0, lineNo: 1, columnNo: 1 },
+    { sheetNo: 2, ruleNo: 1, lineNo: 0, columnNo: 1 },
     { sheetNo: 3, ruleNo: 0, lineNo: 5, columnNo: 6 },
   ];
 
   function doTest() {
+    document.styleSheets[2].insertRule("body{}", 1);
     for (let test of tests) {
       let sheet = document.styleSheets[test.sheetNo];
       let rule = sheet.cssRules[test.ruleNo];