DevTools: deflake extensions-resources.html

LayoutTests/http/tests/inspector/resources/extension-main.js

Index: LayoutTests/http/tests/inspector/resources/extension-main.js
diff --git a/LayoutTests/http/tests/inspector/resources/extension-main.js b/LayoutTests/http/tests/inspector/resources/extension-main.js
index e7196f492cc4143823f6112ad197cb922e5014c7..b331e20786d58a9729c8d0e69e4cf3a8feb85d6b 100644
--- a/LayoutTests/http/tests/inspector/resources/extension-main.js
+++ b/LayoutTests/http/tests/inspector/resources/extension-main.js
@@ -48,6 +48,11 @@ function evaluateOnFrontend(expression, callback)
     window._extensionServerForTests.sendRequest({ command: "evaluateForTestInFrontEnd", expression: expression }, callback);
 }
 
+function invokePageFunctionAsync(functionName, callback)
+{
+    evaluateOnFrontend("InspectorTest.invokePageFunctionAsync('" + functionName + "', reply)", callback);
+}
+
 function output(message)
 {
     evaluateOnFrontend("InspectorTest.addResult(unescape('" + escape(message) + "'));");