Mojo: Use the MessagePipe creation helper whenever possible/reasonable in tests.

mojo/public/cpp/bindings/tests/handle_passing_unittest.cc

Index: mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc b/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
index 7f886b69f5f2e7282bc7a55ae805fa0b8bfeeb8c..f9968520e80096d43e1ae6bdb5411cf5e0309867 100644
--- a/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
@@ -176,20 +176,16 @@ TEST_F(HandlePassingTest, Basic) {
 
   factory.set_client(&factory_client);
 
-  ScopedMessagePipeHandle pipe0, pipe1;
-  CreateMessagePipe(&pipe0, &pipe1);
+  MessagePipe pipe0;
+  EXPECT_TRUE(WriteTextMessage(pipe0.handle1.get(), kText1));
 
-  EXPECT_TRUE(WriteTextMessage(pipe1.get(), kText1));
-
-  ScopedMessagePipeHandle pipe2, pipe3;
-  CreateMessagePipe(&pipe2, &pipe3);
-
-  EXPECT_TRUE(WriteTextMessage(pipe3.get(), kText2));
+  MessagePipe pipe1;
+  EXPECT_TRUE(WriteTextMessage(pipe1.handle1.get(), kText2));
 
   sample::RequestPtr request(sample::Request::New());
   request->x = 1;
-  request->pipe = pipe2.Pass();
-  factory->DoStuff(request.Pass(), pipe0.Pass());
+  request->pipe = pipe1.handle0.Pass();
+  factory->DoStuff(request.Pass(), pipe0.handle0.Pass());
 
   EXPECT_FALSE(factory_client.got_response());