Remove requirement that mojo::Environment be instantiated.

mojo/public/cpp/environment/tests/async_wait_unittest.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 <string>
 
 #include "mojo/public/c/environment/async_waiter.h"
 #include "mojo/public/c/system/result.h"
 #include "mojo/public/c/system/time.h"
 #include "mojo/public/cpp/environment/environment.h"
@@ skipping 43 matching lines @@
 
 void CallCancelWait(MojoAsyncWaitID wait_id) {
   Environment::GetDefaultAsyncWaiter()->CancelWait(wait_id);
 }
 
 class AsyncWaitTest : public testing::Test {
  public:
   AsyncWaitTest() {}
 
  private:
-  Environment environment_;
   RunLoop run_loop_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(AsyncWaitTest);
 };
 
 // Verifies AsyncWaitCallback is notified when pipe is ready.
 TEST_F(AsyncWaitTest, CallbackNotified) {
   TestAsyncWaitCallback callback;
   MessagePipe test_pipe;
   EXPECT_TRUE(test::WriteTextMessage(test_pipe.handle1.get(), std::string()));
@@ skipping 33 matching lines @@
   EXPECT_TRUE(test::WriteTextMessage(test_pipe.handle1.get(), std::string()));
 
   CallCancelWait(CallAsyncWait(
       test_pipe.handle0.get(), MOJO_HANDLE_SIGNAL_READABLE, &callback));
   RunLoop::current()->Run();
   EXPECT_EQ(0, callback.result_count());
 }
 
 }  // namespace
 }  // namespace mojo