Revert of Introduce InterfaceEndpointClient(IEC), InterfaceEndpointHandle and

mojo/public/js/tests/validation_unittest.js

Index: mojo/public/js/tests/validation_unittest.js
diff --git a/mojo/public/js/tests/validation_unittest.js b/mojo/public/js/tests/validation_unittest.js
index 2a07315436e84113f095b189b8e8d80c04a59c8b..2a70248e662ef561f0fa900b4ac51c3c6ab8f6c3 100644
--- a/mojo/public/js/tests/validation_unittest.js
+++ b/mojo/public/js/tests/validation_unittest.js
@@ -278,9 +278,15 @@
     expect(testMessagePipe.result).toBe(core.RESULT_OK);
 
     endpoint.bind(testMessagePipe.handle1);
-    var observer = validator.ValidationErrorObserverForTesting.getInstance();
+    var testingController = endpoint.enableTestingMode();
+
+    var validationError;
+    testingController.setInvalidIncomingMessageHandler(function(error) {
+      validationError = error;
+    });
 
     for (var i = 0; i < testFiles.length; i++) {
+      validationError = noError;
       var testMessage = readTestMessage(testFiles[i]);
       var handles = new Array(testMessage.handleCount);
 
@@ -291,9 +297,8 @@
           core.WRITE_MESSAGE_FLAG_NONE);
       expect(writeMessageValue).toBe(core.RESULT_OK);
 
-      endpoint.waitForNextMessageForTesting();
-      checkValidationResult(testFiles[i], observer.lastError);
-      observer.reset();
+      testingController.waitForNextMessage();
+      checkValidationResult(testFiles[i], validationError);
     }
 
     expect(core.close(testMessagePipe.handle0)).toBe(core.RESULT_OK);
@@ -328,7 +333,6 @@
   testIntegratedMessageHeaderValidation();
   testIntegratedResponseMessageValidation();
   testIntegratedRequestMessageValidation();
-  validator.clearTestingMode();
 
   this.result = "PASS";
 });