Mojo: Add basic logging facilities to environment.

mojo/environment/default_logger.cc

Index: mojo/environment/default_logger.cc
diff --git a/mojo/environment/default_async_waiter.cc b/mojo/environment/default_logger.cc
similarity index 50%
copy from mojo/environment/default_async_waiter.cc
copy to mojo/environment/default_logger.cc
index bbd722963a5f5cf7aa4233b8f6f5834d27b1dbc2..150dfa24824ab67625276b7b1400b593a8ae3709 100644
--- a/mojo/environment/default_async_waiter.cc
+++ b/mojo/environment/default_logger.cc
@@ -2,14 +2,14 @@
 // 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/default_async_waiter.h"
+#include "mojo/public/cpp/environment/default_logger.h"
 
-#include "mojo/environment/default_async_waiter_impl.h"
+#include "mojo/environment/default_logger_impl.h"
 
 namespace mojo {
 
-MojoAsyncWaiter* GetDefaultAsyncWaiter() {
-  return internal::GetDefaultAsyncWaiterImpl();
+const MojoLogger* GetDefaultLogger() {
+  return internal::GetDefaultLoggerImpl();
 }
 
 }  // namespace mojo