Fix styleguide violations from https://codereview.chromium.org/1681363003

tools/gn/command_help.cc

 // Copyright (c) 2013 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 <algorithm>
 #include <iostream>
 
 #include "base/command_line.h"
 #include "tools/gn/args.h"
 #include "tools/gn/commands.h"
@@ skipping 204 matching lines @@
       variables::GetTargetVariables();
   auto found_target_var = target_vars.find(what);
   if (found_target_var != target_vars.end()) {
     PrintLongHelp(found_target_var->second.help);
     return 0;
   }
   for (const auto& entry : target_vars)
     all_help_topics.push_back(entry.first);
 
   // Random other topics.
-  std::map<std::string, std::function<void()>> random_topics;
+  std::map<std::string, void(*)()> random_topics;
   random_topics["all"] = PrintAllHelp;
-  random_topics["buildargs"] = [=]() { PrintLongHelp(kBuildArgs_Help); };
-  random_topics["dotfile"] = [=]() { PrintLongHelp(kDotfile_Help); };
-  random_topics["grammar"] = [=]() { PrintLongHelp(kGrammar_Help); };
-  random_topics["input_conversion"] = [=]() {
+  random_topics["buildargs"] = []() { PrintLongHelp(kBuildArgs_Help); };
+  random_topics["dotfile"] = []() { PrintLongHelp(kDotfile_Help); };
+  random_topics["grammar"] = []() { PrintLongHelp(kGrammar_Help); };
+  random_topics["input_conversion"] = []() {
     PrintLongHelp(kInputConversion_Help);
   };
-  random_topics["label_pattern"] = [=]() { PrintLongHelp(kLabelPattern_Help); };
-  random_topics["runtime_deps"] = [=]() { PrintLongHelp(kRuntimeDeps_Help); };
-  random_topics["source_expansion"] = [=]() {
+  random_topics["label_pattern"] = []() { PrintLongHelp(kLabelPattern_Help); };
+  random_topics["runtime_deps"] = []() { PrintLongHelp(kRuntimeDeps_Help); };
+  random_topics["source_expansion"] = []() {
     PrintLongHelp(kSourceExpansion_Help);
   };
   random_topics["switches"] = PrintSwitchHelp;
   auto found_random_topic = random_topics.find(what);
   if (found_random_topic != random_topics.end()) {
     found_random_topic->second();
     return 0;
   }
   for (const auto& entry : random_topics)
     all_help_topics.push_back(entry.first);
 
   // No help on this.
   Err(Location(), "No help on \"" + what + "\".").PrintToStdout();
   base::StringPiece suggestion = SpellcheckString(what, all_help_topics);
   if (suggestion.empty()) {
     OutputString("Run `gn help` for a list of available topics.\n",
                  DECORATION_NONE);
   } else {
     OutputString("Did you mean `gn help " + suggestion.as_string() + "`?\n",
                  DECORATION_NONE);
   }
   return 1;
 }
 
 }  // namespace commands