DevTools: validate protocol input parameters.

third_party/WebKit/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 15 matching lines @@
         InspectorTest.dumpStyleSheetText(styleSheetId, callback);
     }
 
     function onResponse(message)
     {
         if (!message.error) {
             InspectorTest.log("ERROR: protocol method call did not return expected error. Instead, the following message was received: " + JSON.stringify(message));
             InspectorTest.completeTest();
             return;
         }
-        InspectorTest.log("Expected protocol error: " + message.error.message);
+        InspectorTest.log("Expected protocol error: " + message.error.message + (message.error.data ? " (" + message.error.data + ")" : ""));
         callback();
     }
 }
 
 InspectorTest.setPropertyText = modifyStyleSheet.bind(null, "CSS.setPropertyText", true);
 InspectorTest.setRuleSelector = modifyStyleSheet.bind(null, "CSS.setRuleSelector", true);
 InspectorTest.setMediaText = modifyStyleSheet.bind(null, "CSS.setMediaText", true);
 InspectorTest.addRule = modifyStyleSheet.bind(null, "CSS.addRule", true);
 InspectorTest.setStyleTexts = function(styleSheetId, expectError, edits, callback)
 {
@@ skipping 147 matching lines @@
     {
         if (!omitLog)
             InspectorTest.log("Dumping inline style: ");
         InspectorTest.log("{");
         InspectorTest.dumpStyle(result.inlineStyle, 0);
         InspectorTest.log("}");
         InspectorTest.loadAndDumpMatchingRulesForNode(nodeId, callback, omitLog)
     }
 }
 }