Implement new password separated sign in flow for chrome.
This is currently behind a flag to allow chrome and GAIA UX folks to play
with the feature.

BUG=533004

Review URL: https://codereview.chromium.org/1344443002

Cr-Commit-Position: refs/heads/master@{#352598}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 2fe6524..b3a5ad7 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1397,6 +1397,12 @@
      IDS_FLAGS_ENABLE_IFRAME_BASED_SIGNIN_DESCRIPTION,
      kOsMac | kOsWin | kOsLinux,
      SINGLE_VALUE_TYPE(switches::kEnableIframeBasedSignin)},
+    {"enable-password-separated-signin-flow",
+     IDS_FLAGS_ENABLE_PASSWORD_SEPARATED_SIGNIN_FLOW_NAME,
+     IDS_FLAGS_ENABLE_PASSWORD_SEPARATED_SIGNIN_FLOW_DESCRIPTION,
+     kOsWin | kOsLinux,
+     ENABLE_DISABLE_VALUE_TYPE(switches::kEnablePasswordSeparatedSigninFlow,
+                               switches::kDisablePasswordSeparatedSigninFlow)},
     {"enable-google-profile-info",
      IDS_FLAGS_ENABLE_GOOGLE_PROFILE_INFO_NAME,
      IDS_FLAGS_ENABLE_GOOGLE_PROFILE_INFO_DESCRIPTION,