Mojo: Make GetDefault{AsyncWaiter,Logger} static methods of Environment.

mojo/environment/default_logger_impl.cc

Index: mojo/environment/default_logger_impl.cc
diff --git a/mojo/environment/default_logger_impl.cc b/mojo/environment/default_logger_impl.cc
index 76f76f4a27da970f16f242a048d26d586678979a..575feb3989180f0919efb714163836fe5c210040 100644
--- a/mojo/environment/default_logger_impl.cc
+++ b/mojo/environment/default_logger_impl.cc
@@ -51,9 +51,14 @@ MojoLogLevel GetMinimumLogLevel() {
   return ChromiumToMojoLogLevel(logging::GetMinLogLevel());
 }
 
+void SetMinimumLogLevel(MojoLogLevel log_level) {
+  logging::SetMinLogLevel(MojoToChromiumLogLevel(log_level));
+}
+
 const MojoLogger kDefaultLogger = {
   LogMessage,
-  GetMinimumLogLevel
+  GetMinimumLogLevel,
+  SetMinimumLogLevel
 };
 
 }  // namespace