DevTools: Split creating inspector stylesheet and adding a new rule into stylesheet in protocol.

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

Index: LayoutTests/http/tests/inspector-protocol/inspector-protocol-test.js
diff --git a/LayoutTests/http/tests/inspector-protocol/inspector-protocol-test.js b/LayoutTests/http/tests/inspector-protocol/inspector-protocol-test.js
index 24d460e403ba003799ffa6782f1daccedf98c31b..b1543196a6321a0472e94c1a547af27b6bba389f 100644
--- a/LayoutTests/http/tests/inspector-protocol/inspector-protocol-test.js
+++ b/LayoutTests/http/tests/inspector-protocol/inspector-protocol-test.js
@@ -51,6 +51,21 @@ InspectorTest.sendCommand = function(method, params, handler)
     return this._requestId;
 }
 
+InspectorTest.sendCommandOrDie = function(command, properties, callback)
+{
+    InspectorTest.sendCommand(command, properties || {}, commandCallback);
+    function commandCallback(msg)
+    {
+        if (msg.error) {
+            InspectorTest.log("ERROR: " + msg.error.message);
+            InspectorTest.completeTest();
+            return;
+        }
+        if (callback)
+            callback(msg.result);
+    }
+}
+
 /**
  * @param {function(object)=} callback
  */