Mojo C++ bindings: support closing [Associated]InterfaceRequest with reason.

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <stdint.h>
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 950 matching lines @@
         EXPECT_EQ("farewell", description);
         quit_closure.Run();
       },
       run_loop.QuitClosure()));
 
   impl.binding()->CloseWithReason(456u, "farewell");
 
   run_loop.Run();
 }
 
+TEST_F(AssociatedInterfaceTest, AssociatedRequestResetWithReason) {
+  AssociatedInterfaceRequest<IntegerSender> request;
+  IntegerSenderAssociatedPtrInfo ptr_info;
+  CreateIntegerSender(&ptr_info, &request);
+
+  AssociatedInterfacePtr<IntegerSender> ptr;
+  ptr.Bind(std::move(ptr_info));
+
+  base::RunLoop run_loop;
+  ptr.set_connection_error_with_reason_handler(base::Bind(
+      [](const base::Closure& quit_closure, uint32_t custom_reason,
+         const std::string& description) {
+        EXPECT_EQ(789u, custom_reason);
+        EXPECT_EQ("long time no see", description);
+        quit_closure.Run();
+      },
+      run_loop.QuitClosure()));
+
+  request.ResetWithReason(789u, "long time no see");
+
+  run_loop.Run();
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace mojo