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

base/command_line.h

Index: base/command_line.h
diff --git a/base/command_line.h b/base/command_line.h
index 85d924a8d31dcf743507ceb518a1cddfb91579b7..19df40c4c478bfa9befe59ad9eefc63f5b33c55f 100644
--- a/base/command_line.h
+++ b/base/command_line.h
@@ -143,7 +143,10 @@ class BASE_EXPORT CommandLine {
 
   // 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.