[Autofill][States] Introduce kAutofillUseAlternativeStateNameMap feature

This CL introduces a feature flag for enabling the use of
AlternativeStateNameMap for the filling of state fields, comparison of
profiles and sending votes to the server.

Bug: 1111960
Change-Id: I03ef197ae4d5efd99c46228f6a2f0ec3c9009590
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2505887
Commit-Queue: Vidhan Jain <vidhanj@google.com>
Reviewed-by: Dominic Battré <battre@chromium.org>
Reviewed-by: Matthias Körber <koerber@google.com>
Cr-Commit-Position: refs/heads/master@{#823227}

components/autofill/core/common/autofill_features.cc

@@ -253,6 +253,13 @@ const base::Feature kAutofillTokenPrefixMatching{
 const base::Feature kAutofillUploadThrottling{"AutofillUploadThrottling",
                                               base::FEATURE_ENABLED_BY_DEFAULT};
 
+// Controls whether to use the AutofillUseAlternativeStateNameMap for filling
+// of state selection fields, comparison of profiles and sending state votes to
+// the server.
+// TODO(crbug.com/1143516): Remove the feature when the experiment is completed.
+const base::Feature kAutofillUseAlternativeStateNameMap{
+    "AutofillUseAlternativeStateNameMap", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Controls whether suggestions' labels use the improved label disambiguation
 // format.
 const base::Feature kAutofillUseImprovedLabelDisambiguation{

components/autofill/core/common/autofill_features.h

@@ -65,6 +65,7 @@ extern const base::Feature kAutofillSkipComparingInferredLabels;
 extern const base::Feature kAutofillSkipFillingFieldsWithChangedValues;
 extern const base::Feature kAutofillTokenPrefixMatching;
 extern const base::Feature kAutofillUploadThrottling;
+extern const base::Feature kAutofillUseAlternativeStateNameMap;
 extern const base::Feature kAutofillUseImprovedLabelDisambiguation;
 extern const base::Feature kAutofillUseNewSectioningMethod;
 extern const base::Feature kAutofillUsePageLanguageToSelectFieldParsingPatterns;