Remove duplicate application cpp files in mojo/application.

mojo/application/public/cpp/application_test_base.h

Index: mojo/application/public/cpp/application_test_base.h
diff --git a/mojo/application/public/cpp/application_test_base.h b/mojo/application/public/cpp/application_test_base.h
index 9314bda23c1a78262f65812420e102990f1c4c2e..5b0fab1074ac95eef4ec4db219826ae2fc631e8a 100644
--- a/mojo/application/public/cpp/application_test_base.h
+++ b/mojo/application/public/cpp/application_test_base.h
@@ -18,9 +18,6 @@ class ApplicationImpl;
 
 namespace test {
 
-// Access the command line arguments passed to the application test.
-const Array<String>& Args();
-
 // Run all application tests. This must be called after the environment is
 // initialized, to support construction of a default run loop.
 MojoResult RunAllTests(MojoHandle application_request_handle);