Require build directories exist for some GN commands.

tools/gn/command_ls.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 <algorithm>
 #include <set>
 
 #include "base/command_line.h"
 #include "tools/gn/commands.h"
 #include "tools/gn/label_pattern.h"
@@ skipping 49 matching lines @@
     "      in multiple toolchains).\n";
 
 int RunLs(const std::vector<std::string>& args) {
   if (args.size() != 1 && args.size() != 2) {
     Err(Location(), "You're holding it wrong.",
         "Usage: \"gn ls <build dir> [<label_pattern>]\"").PrintToStdout();
     return 1;
   }
 
   Setup* setup = new Setup;
-  if (!setup->DoSetup(args[0]) || !setup->Run())
+  if (!setup->DoSetup(args[0], false) || !setup->Run())
     return 1;
 
   const CommandLine* cmdline = CommandLine::ForCurrentProcess();
   bool all_toolchains = cmdline->HasSwitch("all-toolchains");
 
   // Find matching targets.
   std::vector<const Target*> matches;
   if (args.size() == 2) {
     // Given a pattern, match it.
     if (!ResolveTargetsFromCommandLinePattern(setup, args[1], all_toolchains,
@@ skipping 31 matching lines @@
       OutputString(sorted_matches[i].GetUserVisibleName(
           sorted_matches[i].GetToolchainLabel() != default_tc_label));
       OutputString("\n");
     }
   }
 
   return 0;
 }
 
 }  // namespace commands