Provide CommandLine::HasSwitch(const char*) to save 76kB in sizes perf

base/command_line.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.
 
 // 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 124 matching lines @@
 #endif
 
   // Returns the original command line string as a vector of strings.
   const StringVector& argv() const { return argv_; }
 
   // Get and Set the program part of the command line string (the first item).
   FilePath GetProgram() const;
   void SetProgram(const FilePath& program);
 
   // Returns true if this command line contains the given switch.
   // (Switch names are case-insensitive).

[tapted, 2015/03/18 08:51:45]

This comment isn't really true except on Windows....  earlier patchsets rolled
in a change for the new overload to DCHECK that the string constant argument was
lowercase to begin with. But that would be an orthogonal change

mallocing/copying the string *again* every time HasSwitch is called on windows
is probably a non-trivial hit to performance (likely startup path), and would be
good to analyze separately.

+  // The second override provides an optimized version to avoid inlining the
+  // codegen for the string allocation.
   bool HasSwitch(const std::string& switch_string) const;
+  bool HasSwitch(const char switch_constant[]) const;
 
   // Returns the value associated with the given switch. If the switch has no
   // value or isn't present, this method returns the empty string.
   std::string GetSwitchValueASCII(const std::string& switch_string) const;
   FilePath GetSwitchValuePath(const std::string& switch_string) const;
   StringType GetSwitchValueNative(const std::string& switch_string) const;
 
   // Get a copy of all switches, along with their values.
   const SwitchMap& GetSwitches() const { return switches_; }
 
@@ skipping 63 matching lines @@
   // Parsed-out switch keys and values.
   SwitchMap switches_;
 
   // The index after the program and switches, any arguments start here.
   size_t begin_args_;
 };
 
 }  // namespace base
 
 #endif  // BASE_COMMAND_LINE_H_