Add a flag for fill on account select without highlighting

In the fill on account select password manager experiment, the enabled
setting still highlights the fields that can be autofilled. This adds an
experimental group where the fields will not be highlighted even if they
can be autofilled until after a choice has been selected.

[email protected]
[email protected]

BUG=410963

Review URL: https://codereview.chromium.org/788183004

Cr-Commit-Position: refs/heads/master@{#309558}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 963abca9..096cdc0 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -382,6 +382,16 @@
     switches::kSSLVersionTLSv12 },
 };
 
+const Experiment::Choice kFillOnAccountSelectChoices[] = {
+  { IDS_GENERIC_EXPERIMENT_CHOICE_DEFAULT, "", "" },
+  { IDS_GENERIC_EXPERIMENT_CHOICE_DISABLED,
+    autofill::switches::kDisableFillOnAccountSelect, "" },
+  { IDS_FLAGS_FILL_ON_ACCOUNT_SELECT_ENABLE_HIGHLIGHTING,
+    autofill::switches::kEnableFillOnAccountSelect, "" },
+  { IDS_FLAGS_FILL_ON_ACCOUNT_SELECT_ENABLE_NO_HIGHLIGHTING,
+    autofill::switches::kEnableFillOnAccountSelectNoHighlighting, "" },
+};
+
 // RECORDING USER METRICS FOR FLAGS:
 // -----------------------------------------------------------------------------
 // The first line of the experiment is the internal name. If you'd like to
@@ -2084,8 +2094,7 @@
     IDS_FILL_ON_ACCOUNT_SELECT_NAME,
     IDS_FILL_ON_ACCOUNT_SELECT_DESCRIPTION,
     kOsAll,
-    ENABLE_DISABLE_VALUE_TYPE(autofill::switches::kEnableFillOnAccountSelect,
-                              autofill::switches::kDisableFillOnAccountSelect)
+    MULTI_VALUE_TYPE(kFillOnAccountSelectChoices)
   },
 
   // NOTE: Adding new command-line switches requires adding corresponding