DevTools: allow injecting CSS rules without breaking styles sidebar.

LayoutTests/http/tests/inspector-protocol/css-protocol-test.js

 function initialize_cssTest()
 {
 
 InspectorTest.dumpStyleSheetText = function(styleSheetId, callback)
 {
     InspectorTest.sendCommandOrDie("CSS.getStyleSheetText", { styleSheetId: styleSheetId }, onStyleSheetText);
     function onStyleSheetText(result)
     {
         InspectorTest.log("==== Style sheet text ====");
         InspectorTest.log(result.text);
@@ skipping 74 matching lines @@
             selectorLine += ", ";
         var matching = matchingSelectors.indexOf(i) !== -1;
         if (matching)
             selectorLine += "*";
         selectorLine += selectors[i].value;
         if (matching)
             selectorLine += "*";
     }
     selectorLine += " {";
     selectorLine += "    " + rule.origin;
+    if (!rule.style.styleSheetId)
+        selectorLine += "    readonly";
     indentLog(baseIndent, selectorLine);
     InspectorTest.dumpStyle(rule.style, baseIndent);
     indentLog(baseIndent, "}");
 };
 
 InspectorTest.dumpStyle = function(style, baseIndent)
 {
     if (!style)
         return;
     var cssProperties = style.cssProperties;
     for (var i = 0; i < cssProperties.length; ++i) {
         var cssProperty = cssProperties[i];
         var propertyLine = cssProperty.name + ": " + cssProperty.value + ";";
         indentLog(baseIndent + 4, propertyLine);
     }
 }
 
 InspectorTest.displayName = function(url)
 {
     return url.substr(url.lastIndexOf("/") + 1);
 };
 
-InspectorTest.loadAndDumpMatchingRulesForNode = function(nodeId, callback)
+InspectorTest.loadAndDumpMatchingRulesForNode = function(nodeId, callback, omitLog)
 {
     InspectorTest.sendCommandOrDie("CSS.getMatchedStylesForNode", { "nodeId": nodeId }, matchingRulesLoaded);
 
     function matchingRulesLoaded(result)
     {
-        InspectorTest.log("Dumping matched rules: ");
+        if (!omitLog)
+            InspectorTest.log("Dumping matched rules: ");
         dumpRuleMatches(result.matchedCSSRules);
-        InspectorTest.log("Dumping inherited rules: ");
+        if (!omitLog)
+            InspectorTest.log("Dumping inherited rules: ");
         for (var inheritedEntry of result.inherited) {
             InspectorTest.dumpStyle(inheritedEntry.inlineStyle);
             dumpRuleMatches(inheritedEntry.matchedCSSRules);
         }
         callback();
     }
 
     function dumpRuleMatches(ruleMatches)
     {
         for (var ruleMatch of ruleMatches) {
             var origin = ruleMatch.rule.origin;
             if (origin !== "inspector" && origin !== "regular")
                 continue;
             InspectorTest.dumpRuleMatch(ruleMatch);
         }
     }
 }
 
-InspectorTest.loadAndDumpMatchingRules = function(documentNodeId, selector, callback)
+InspectorTest.loadAndDumpMatchingRules = function(documentNodeId, selector, callback, omitLog)
 {
     InspectorTest.requestNodeId(documentNodeId, selector, nodeIdLoaded);
 
     function nodeIdLoaded(nodeId)
     {
-        InspectorTest.loadAndDumpMatchingRulesForNode(nodeId, callback);
+        InspectorTest.loadAndDumpMatchingRulesForNode(nodeId, callback, omitLog);
     }
 }
 
 }