Update from https://crrev.com/316786

base/logging.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_LOGGING_H_
 #define BASE_LOGGING_H_
 
 #include <cassert>
 #include <string>
 #include <cstring>
@@ skipping 332 matching lines @@
   ((::logging::LOG_ ## severity) >= ::logging::GetMinLogLevel())
 
 // We can't do any caching tricks with VLOG_IS_ON() like the
 // google-glog version since it requires GCC extensions.  This means
 // that using the v-logging functions in conjunction with --vmodule
 // may be slow.
 #define VLOG_IS_ON(verboselevel) \
   ((verboselevel) <= ::logging::GetVlogLevel(__FILE__))
 
 // Helper macro which avoids evaluating the arguments to a stream if
-// the condition doesn't hold.
+// the condition doesn't hold. Condition is evaluated once and only once.
 #define LAZY_STREAM(stream, condition)                                  \
   !(condition) ? (void) 0 : ::logging::LogMessageVoidify() & (stream)
 
 // We use the preprocessor's merging operator, "##", so that, e.g.,
 // LOG(INFO) becomes the token COMPACT_GOOGLE_LOG_INFO.  There's some funny
 // subtle difference between ostream member streaming functions (e.g.,
 // ostream::operator<<(int) and ostream non-member streaming functions
 // (e.g., ::operator<<(ostream&, string&): it turns out that it's
 // impossible to stream something like a string directly to an unnamed
 // ostream. We employ a neat hack by calling the stream() member
@@ skipping 562 matching lines @@
 #elif NOTIMPLEMENTED_POLICY == 5
 #define NOTIMPLEMENTED() do {\
   static bool logged_once = false;\
   LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\
   logged_once = true;\
 } while(0);\
 EAT_STREAM_PARAMETERS
 #endif
 
 #endif  // BASE_LOGGING_H_