Mojo C++ bindings: support disconnect with a reason.

mojo/public/cpp/bindings/tests/binding_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.
 
 // Note: This file tests both binding.h (mojo::Binding) and strong_binding.h
 // (mojo::StrongBinding).
 
 #include "mojo/public/cpp/bindings/binding.h"
 
 #include <stdint.h>
@@ skipping 406 matching lines @@
   Binding<sample::Service> binding(&impl, std::move(request));
   binding.set_connection_error_handler(SetFlagAndRunClosure(&called));
   ptr.reset();
 
   EXPECT_FALSE(called);
   binding.FlushForTesting();
   EXPECT_TRUE(called);
   binding.FlushForTesting();
 }
 
+TEST_F(BindingTest, ConnectionErrorWithReason) {
+  sample::ServicePtr ptr;
+  auto request = GetProxy(&ptr);
+  ServiceImpl impl;
+  Binding<sample::Service> binding(&impl, std::move(request));
+
+  base::RunLoop run_loop;
+  binding.set_connection_error_with_reason_handler(base::Bind(
+      [](const base::Closure& quit_closure, uint32_t custom_reason,
+         const std::string& description) {
+        EXPECT_EQ(1234u, custom_reason);
+        EXPECT_EQ("hello", description);
+        quit_closure.Run();
+      },
+      run_loop.QuitClosure()));
+
+  ptr.ResetWithReason(1234u, "hello");
+
+  run_loop.Run();
+}
+
 // StrongBindingTest -----------------------------------------------------------
 
 using StrongBindingTest = BindingTestBase;
 
 // Tests that destroying a mojo::StrongBinding closes the bound message pipe
 // handle but does *not* destroy the implementation object.
 TEST_F(StrongBindingTest, DestroyClosesMessagePipe) {
   base::RunLoop run_loop;
   bool encountered_error = false;
   bool was_deleted = false;
@@ skipping 82 matching lines @@
 
   EXPECT_FALSE(called);
   EXPECT_FALSE(was_deleted);
   ASSERT_TRUE(binding);
   binding->FlushForTesting();
   EXPECT_TRUE(called);
   EXPECT_TRUE(was_deleted);
   ASSERT_FALSE(binding);
 }
 
+TEST_F(StrongBindingTest, ConnectionErrorWithReason) {
+  sample::ServicePtr ptr;
+  auto request = GetProxy(&ptr);
+  auto binding =
+      MakeStrongBinding(base::MakeUnique<ServiceImpl>(), std::move(request));
+  base::RunLoop run_loop;
+  binding->set_connection_error_with_reason_handler(base::Bind(
+      [](const base::Closure& quit_closure, uint32_t custom_reason,
+         const std::string& description) {
+        EXPECT_EQ(5678u, custom_reason);
+        EXPECT_EQ("hello", description);
+        quit_closure.Run();
+      },
+      run_loop.QuitClosure()));
+
+  ptr.ResetWithReason(5678u, "hello");
+
+  run_loop.Run();
+}
+
 }  // namespace
 }  // mojo