gn: Check GN_EDITOR before EDITOR in environment variables.

tools/gn/command_args.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 <stdio.h>
 #include <stdlib.h>
 
 #include <map>
 
 #include "base/command_line.h"
@@ skipping 178 matching lines @@
                  "\"...\n");
     ::WaitForSingleObject(info.hProcess, INFINITE);
     ::CloseHandle(info.hProcess);
   }
   return true;
 }
 
 #else  // POSIX
 
 bool RunEditor(const base::FilePath& file_to_edit) {
   // Prefer $VISUAL, then $EDITOR, then vi.

[brettw, 2014/10/15 21:11:20]

Maybe just remove this comment?

   const char* editor_ptr = getenv("VISUAL");
   if (!editor_ptr)
+    editor_ptr = getenv("GN_EDITOR");
+  if (!editor_ptr)
     editor_ptr = getenv("EDITOR");
   if (!editor_ptr)
     editor_ptr = "vi";
 
   std::string cmd(editor_ptr);
   cmd.append(" \"");
 
   // Its impossible to do this properly since we don't know the user's shell,
   // but quoting and escaping internal quotes should handle 99.999% of all
   // cases.
@@ skipping 123 matching lines @@
         "Or see \"gn help args\" for more variants.").PrintToStdout();
     return 1;
   }
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(kSwitchList))
     return ListArgs(args[0]);
   return EditArgsFile(args[0]);
 }
 
 }  // namespace commands