Convert filesystem_apptests to shelltests.

mojo/shell/public/cpp/lib/shell_test.cc

 // Copyright 2016 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 "mojo/shell/public/cpp/shell_test.h"
 
 #include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "mojo/shell/background/background_shell.h"
 #include "mojo/shell/public/cpp/shell_client.h"
 
 namespace mojo {
 namespace test {
 
 ShellTestClient::ShellTestClient(ShellTest* test) : test_(test) {}
 ShellTestClient::~ShellTestClient() {}
 
 void ShellTestClient::Initialize(Connector* connector, const Identity& identity,
@@ skipping 19 matching lines @@
 }
 
 void ShellTest::InitializeCalled(Connector* connector,
                                  const std::string& name,
                                  const std::string& user_id,
                                  uint32_t id) {
   DCHECK_EQ(connector_, connector);
   initialize_name_ = name;
   initialize_instance_id_ = id;
   initialize_userid_ = user_id;
+  initialize_called_.Run();
 }
 
 void ShellTest::SetUp() {
   shell_client_ = CreateShellClient();
   message_loop_ = CreateMessageLoop();
   background_shell_.reset(new shell::BackgroundShell);
   background_shell_->Init(nullptr);
+
+  // Create the shell connection. We don't proceed until we get our
+  // ShellClient's Initialize() method is called.
+  base::RunLoop run_loop;

[yzshen1, 2016/03/17 22:56:57]

I am personally fine with this, but not sure whether we want this behavior with
all shell tests. You might want to confirm with Ben.

+  base::MessageLoop::ScopedNestableTaskAllower allow(
+      base::MessageLoop::current());
+  initialize_called_ = run_loop.QuitClosure();
+
   shell_connection_.reset(new ShellConnection(
       shell_client_.get(),
       background_shell_->CreateShellClientRequest(test_name_)));
   connector_ = shell_connection_->connector();
+
+  run_loop.Run();
 }
 
 void ShellTest::TearDown() {
   shell_connection_.reset();
   background_shell_.reset();
   message_loop_.reset();
   shell_client_.reset();
 }
 
 }  // namespace test
 }  // namespace mojo