Put code in //services/js in namespace js

services/js/echo_apptest.cc

 // Copyright 2014 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 "services/js/test/echo_service.mojom.h"
 #include "services/js/test/js_application_test_base.h"
 
-namespace mojo {
+using mojo::String;
+
+namespace js {
 namespace {
 
 class JSEchoTest : public test::JSApplicationTestBase {
  public:
   JSEchoTest() : JSApplicationTestBase() {}
   ~JSEchoTest() override {}
 
  protected:
   // ApplicationTestBase:
   void SetUp() override {
     ApplicationTestBase::SetUp();
     const std::string& url = JSAppURL("echo.js");
     application_impl()->ConnectToService(url, &echo_service_);
   }
 
-  EchoServicePtr echo_service_;
+  mojo::EchoServicePtr echo_service_;
 
  private:
   MOJO_DISALLOW_COPY_AND_ASSIGN(JSEchoTest);
 };
 
 struct EchoStringCallback {
   explicit EchoStringCallback(String *s) : echo_value(s) {}
   void Run(const String& value) const {
     *echo_value = value;
   }
@@ skipping 21 matching lines @@
 TEST_F(JSEchoTest, EchoNullString) {
   String null;
   EchoStringCallback callback(&null);
   echo_service_->EchoString(nullptr, callback);
   EXPECT_TRUE(echo_service_.WaitForIncomingMethodCall());
   EXPECT_TRUE(null.is_null());
   echo_service_->EchoString("quit", callback);
 }
 
 } // namespace
-} // namespace mojo
+}  // namespace js