Use StringPiece for base CommandLine::HasSwitch

base/command_line.cc

Index: base/command_line.cc
diff --git a/base/command_line.cc b/base/command_line.cc
index 6125667d3ec8e66dcead5ec8147fd5879bd6ad48..f6c435391587f10e075df02a2b486e4cf86c01a5 100644
--- a/base/command_line.cc
+++ b/base/command_line.cc
@@ -93,14 +93,14 @@ void AppendSwitchesAndArguments(CommandLine* command_line,
   }
 }
 
-// Lowercase switches for backwards compatiblity *on Windows*.
+// Lowercase switches for backwards compatibility *on Windows*.
 #if defined(OS_WIN)
-std::string LowerASCIIOnWindows(const std::string& string) {
-  return StringToLowerASCII(string);
+std::string LowerASCIIOnWindows(const base::StringPiece& string) {
+  return StringToLowerASCII(string.as_string());
 }
 #elif defined(OS_POSIX)
-const std::string& LowerASCIIOnWindows(const std::string& string) {
-  return string;
+std::string LowerASCIIOnWindows(const base::StringPiece& string) {
+  return string.as_string();
 }
 #endif
 
@@ -262,7 +262,7 @@ void CommandLine::SetProgram(const FilePath& program) {
   TrimWhitespace(program.value(), TRIM_ALL, &argv_[0]);
 }
 
-bool CommandLine::HasSwitch(const std::string& switch_string) const {
+bool CommandLine::HasSwitch(const base::StringPiece& switch_string) const {
   return switches_.find(LowerASCIIOnWindows(switch_string)) != switches_.end();
 }