[autofill] Add support for PSL domain matching for password autofill.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 93a192373a08c50259e1ee01e87757eceae83120..edbd55219ba2d6b2a85c27af86b22362ba81fe39 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -494,6 +494,10 @@ const char kEnableAsyncDns[]                = "enable-async-dns";
 // HttpAuthHandlerNegotiate::CreateSPN for more background.
 const char kEnableAuthNegotiatePort[]       = "enable-auth-negotiate-port";
 
+// Enable using a PSL-based domain matching for autofill of passwords.
+const char kEnablePasswordAutofillPSLDomainMatching[] =
+    "enable-password-autofill-psl-domain-matching";
+
 // Enables the pre- and auto-login features. When a user signs in to sync, the
 // browser's cookie jar is pre-filled with GAIA cookies. When the user visits a
 // GAIA login page, an info bar can help the user login.