Don't evaluate args to LOG(INFO) and LOG(WARNING) in release builds.

base/logging.cc

Index: base/logging.cc
diff --git a/base/logging.cc b/base/logging.cc
index 650351d837e39fefdb9223c757840bcc18cd7cb4..2aedbef44752ac89b3fb5a76f071b8af15fe9784 100644
--- a/base/logging.cc
+++ b/base/logging.cc
@@ -390,6 +390,15 @@ int GetMinLogLevel() {
   return g_min_log_level;
 }
 
+bool ShouldCreateLogMessage(int severity) {
+  if (severity < g_min_log_level)
+    return false;
+
+  // These are the cases for which ~LogMessage does something.
+  return g_logging_destination != LOG_NONE || log_message_handler ||
+         severity >= kAlwaysPrintErrorLevel;

[brettw, 2015/12/03 23:52:14]

Do ew need the kAlwaysPrintErrorLevel check here? If there is no destinatoin and
no message handler, can even LOG_FATAL go anywhere? If this is needed, we should
mention in the comment why.

[skobes, 2015/12/03 23:57:26]

Yeah, ~LogMessage writes to stderr if severity_ >= kAlwaysPrintErrorLevel, even
when g_logging_destination is LOG_NONE.

I tried to capture this in the comment... is there another way of wording it
that you'd prefer?

+}
+
 int GetVlogVerbosity() {
   return std::max(-1, LOG_INFO - GetMinLogLevel());
 }