Allow callers of CommandLine::Init to know whether they were the first caller.

base/command_line.h

 // Copyright (c) 2011 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.
 
 // This class works with command lines: building and parsing.
 // Arguments with prefixes ('--', '-', and on Windows, '/') are switches.
 // Switches will precede all other arguments without switch prefixes.
 // Switches can optionally have values, delimited by '=', e.g., "-switch=value".
 // An argument of "--" will terminate switch parsing during initialization,
 // interpreting subsequent tokens as non-switch arguments, regardless of prefix.
@@ skipping 37 matching lines @@
 
   // Construct a new command line from an argument list.
   CommandLine(int argc, const CharType* const* argv);
   explicit CommandLine(const StringVector& argv);
 
   ~CommandLine();
 
   // Initialize the current process CommandLine singleton. On Windows, ignores
   // its arguments (we instead parse GetCommandLineW() directly) because we
   // don't trust the CRT's parsing of the command line, but it still must be
-  // called to set up the command line.
-  static void Init(int argc, const char* const* argv);
+  // called to set up the command line. Returns false if initialization has
+  // already occurred, and true otherwise. Only the caller receiving a 'true'
+  // return value should take responsibility for calling Reset.
+  static bool Init(int argc, const char* const* argv);
 
   // Destroys the current process CommandLine singleton. This is necessary if
   // you want to reset the base library to its initial state (for example, in an
   // outer library that needs to be able to terminate, and be re-initialized).
   // If Init is called only once, as in main(), Reset() is not necessary.
   static void Reset();
 
   // Get the singleton CommandLine representing the current process's
   // command line. Note: returned value is mutable, but not thread safe;
   // only mutate if you know what you're doing!
@@ skipping 86 matching lines @@
   StringVector argv_;
 
   // Parsed-out switch keys and values.
   SwitchMap switches_;
 
   // The index after the program and switches, any arguments start here.
   size_t begin_args_;
 };
 
 #endif  // BASE_COMMAND_LINE_H_