Added user email/password switches for test automation.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
===================================================================
--- chrome/common/chrome_switches.cc	(revision 98804)
+++ chrome/common/chrome_switches.cc	(working copy)
@@ -1122,6 +1122,10 @@
 // Enables overriding the path for the default authentication extension.
 const char kAuthExtensionPath[]             = "auth-ext-path";
 
+// Enables overriding user credential for GAIA login.
+const char kTestAuthEmail[]                 = "test-auth-email";
+const char kTestAuthPassword[]              = "test-auth-password";
+
 // Enables archive file (zip) handling in file manager.
 const char kEnableArchives[]                = "enable-archives";