Add read-only mode to CommandLine that optimizes HasSwitch(const char*).

base/command_line_unittest.cc

Index: base/command_line_unittest.cc
diff --git a/base/command_line_unittest.cc b/base/command_line_unittest.cc
index e395c85677ab3f36844e9572b535e8f4d77adc90..49f296f33490f4b3c816b20159c177d89ed2d35b 100644
--- a/base/command_line_unittest.cc
+++ b/base/command_line_unittest.cc
@@ -60,11 +60,12 @@ TEST(CommandLineTest, CommandLineConstructor) {
             cl.GetProgram().value());
 
   EXPECT_TRUE(cl.HasSwitch("foo"));
-  EXPECT_TRUE(cl.HasSwitch("bAr"));
+  EXPECT_TRUE(cl.HasSwitch(std::string("bAr")));
+  EXPECT_DEBUG_DEATH(cl.HasSwitch("bAr"), "");
   EXPECT_TRUE(cl.HasSwitch("baz"));
   EXPECT_TRUE(cl.HasSwitch("spaetzle"));
 #if defined(OS_WIN)
-  EXPECT_TRUE(cl.HasSwitch("SPAETZLE"));
+  EXPECT_TRUE(cl.HasSwitch(std::string("SPAETZLE")));
 #endif
   EXPECT_TRUE(cl.HasSwitch("other-switches"));
   EXPECT_TRUE(cl.HasSwitch("input-translation"));
@@ -128,7 +129,7 @@ TEST(CommandLineTest, CommandLineFromString) {
   EXPECT_TRUE(cl.HasSwitch("bar"));
   EXPECT_TRUE(cl.HasSwitch("baz"));
   EXPECT_TRUE(cl.HasSwitch("spaetzle"));
-  EXPECT_TRUE(cl.HasSwitch("SPAETZLE"));
+  EXPECT_TRUE(cl.HasSwitch(std::string("SPAETZLE")));
   EXPECT_TRUE(cl.HasSwitch("other-switches"));
   EXPECT_TRUE(cl.HasSwitch("input-translation"));
   EXPECT_TRUE(cl.HasSwitch("quotes"));