Remove requirement that mojo::Environment be instantiated.

mojo/public/cpp/environment/lib/environment.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 "mojo/public/cpp/environment/environment.h"
 
 #include <assert.h>
 
 #include "mojo/public/c/environment/logger.h"
 #include "mojo/public/cpp/environment/lib/default_async_waiter.h"
 #include "mojo/public/cpp/environment/lib/default_logger.h"
 #include "mojo/public/cpp/utility/run_loop.h"
 
 namespace mojo {
 
-namespace {
-
-const MojoAsyncWaiter* g_default_async_waiter = nullptr;
-const MojoLogger* g_default_logger = nullptr;
-
-void Init(const MojoAsyncWaiter* default_async_waiter,
-          const MojoLogger* default_logger) {
-  g_default_async_waiter = default_async_waiter
-                               ? default_async_waiter
-                               : &internal::kDefaultAsyncWaiter;
-  g_default_logger =
-      default_logger ? default_logger : &internal::kDefaultLogger;
-}
-
-}  // namespace
-
-Environment::Environment() {
-  Init(nullptr, nullptr);
-}
-
-Environment::Environment(const MojoAsyncWaiter* default_async_waiter,
-                         const MojoLogger* default_logger) {
-  Init(default_async_waiter, default_logger);
-}
-
-Environment::~Environment() {
-  // TODO(vtl): Maybe we should allow nesting, and restore previous default
-  // async waiters and loggers?
-  g_default_async_waiter = nullptr;
-  g_default_logger = nullptr;
-}
+const MojoAsyncWaiter* g_default_async_waiter = &internal::kDefaultAsyncWaiter;
+const MojoLogger* g_default_logger = &internal::kDefaultLogger;
 
 // static
 const MojoAsyncWaiter* Environment::GetDefaultAsyncWaiter() {
-  assert(g_default_async_waiter);  // Fails if not "inside" |Environment|.
   return g_default_async_waiter;
 }
 
 // static
+void Environment::SetDefaultAsyncWaiter(const MojoAsyncWaiter* async_waiter) {
+  g_default_async_waiter =
+      async_waiter ? async_waiter : &internal::kDefaultAsyncWaiter;
+}
+
+// static
 const MojoLogger* Environment::GetDefaultLogger() {
-  assert(g_default_logger);  // Fails if not "inside" |Environment|.
   return g_default_logger;
 }
 
 // static
 void Environment::SetDefaultLogger(const MojoLogger* logger) {
-  assert(g_default_logger);  // Fails if not "inside" |Environment|.
   g_default_logger = logger ? logger : &internal::kDefaultLogger;
 }
 
 // static
 void Environment::InstantiateDefaultRunLoop() {
   assert(!RunLoop::current());
   // Not leaked: accessible from |RunLoop::current()|.
   RunLoop* run_loop = new RunLoop();
   MOJO_ALLOW_UNUSED_LOCAL(run_loop);
   assert(run_loop == RunLoop::current());
 }
 
 // static
 void Environment::DestroyDefaultRunLoop() {
   assert(RunLoop::current());
   delete RunLoop::current();
   assert(!RunLoop::current());
 }
 
 }  // namespace mojo