[DevTools] Move extension embedder message to InspectorFrontentAPI.

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

Index: LayoutTests/http/tests/inspector/extensions-test.js
diff --git a/LayoutTests/http/tests/inspector/extensions-test.js b/LayoutTests/http/tests/inspector/extensions-test.js
index a168c54881878e52c2b3154f542a9e33808635db..ccb95713675dbb295308ea3d7928d4ef033ca2d9 100644
--- a/LayoutTests/http/tests/inspector/extensions-test.js
+++ b/LayoutTests/http/tests/inspector/extensions-test.js
@@ -12,7 +12,7 @@ function extensionFunctions()
 var initialize_ExtensionsTest = function()
 {
 
-WebInspector.extensionServer._overridePlatformExtensionAPIForTest = function(extensionInfo)
+WebInspector.extensionServer._overridePlatformExtensionAPIForTest = function(extensionInfo, inspectedTabId)
 {
     WebInspector.extensionServer._registerHandler("evaluateForTestInFrontEnd", onEvaluate);
 
@@ -61,7 +61,7 @@ InspectorTest.runExtensionTests = function()
             pageURL.replace(/^(https?:\/\/[^/]*\/).*$/,"$1") :
             pageURL.replace(/\/inspector\/extensions\/[^/]*$/, "/http/tests")) +
             "/inspector/resources/extension-main.html";
-        WebInspector.addExtensions([{ startPage: extensionURL, name: "test extension", exposeWebInspectorNamespace: true }]);
+        InspectorFrontendAPI.addExtensions([{ startPage: extensionURL, name: "test extension", exposeWebInspectorNamespace: true }]);
         WebInspector.extensionServer.initializeExtensions();
     });
 }