Mojo: Add basic logging facilities to environment.

mojo/environment/default_logger_impl.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/environment/default_logger_impl.h"
+
+#include "base/logging.h"
+#include "base/macros.h"
+
+namespace mojo {
+namespace internal {
+namespace {
+
+int GetChromiumLogLevel(MojoLogLevel log_level) {
+  // Our log levels correspond, except for "fatal":
+  COMPILE_ASSERT(logging::LOG_VERBOSE == MOJO_LOG_LEVEL_VERBOSE,
+                 verbose_log_level_value_mismatch);
+  COMPILE_ASSERT(logging::LOG_INFO == MOJO_LOG_LEVEL_INFO,
+                 info_log_level_value_mismatch);
+  COMPILE_ASSERT(logging::LOG_WARNING == MOJO_LOG_LEVEL_WARNING,
+                 warning_log_level_value_mismatch);
+  COMPILE_ASSERT(logging::LOG_ERROR == MOJO_LOG_LEVEL_ERROR,
+                 error_log_level_value_mismatch);
+
+  return (log_level >= MOJO_LOG_LEVEL_FATAL) ? logging::LOG_FATAL : log_level;
+}
+
+void LogMessage(MojoLogLevel log_level, const char* message) {
+  // TODO(vtl): Possibly, we should try to pull out the file and line number
+  // from |message|.
+  logging::LogMessage(__FILE__, __LINE__,

[darin (slow to review), 2014/06/14 06:08:23]

it seems like MojoLogger::LogMessage should probably take file and lineno
parameters.

+                      GetChromiumLogLevel(log_level)).stream() << message;
+}
+
+const MojoLogger kDefaultLogger = {
+  LogMessage
+};
+
+}  // namespace
+
+const MojoLogger* GetDefaultLoggerImpl() {
+  return &kDefaultLogger;
+}
+
+}  // namespace internal
+}  // namespace mojo