[Autofill] Add metrics to determine whether the system AddressBook is accessible.

components/autofill/core/common/autofill_pref_names.h

Index: components/autofill/core/common/autofill_pref_names.h
diff --git a/components/autofill/core/common/autofill_pref_names.h b/components/autofill/core/common/autofill_pref_names.h
index e52cc7285f87e8053e9ca722f30ecfceb9ec174a..50af375f22f88b7f33ec298ddeb31f21f321c9e1 100644
--- a/components/autofill/core/common/autofill_pref_names.h
+++ b/components/autofill/core/common/autofill_pref_names.h
@@ -11,6 +11,7 @@ namespace prefs {
 // Alphabetical list of preference names specific to the Autofill
 // component. Keep alphabetized, and document each in the .cc file.
 extern const char kAutofillAuxiliaryProfilesEnabled[];
+extern const char kAutofillAuxiliaryProfilesQueried[];
 extern const char kAutofillEnabled[];
 extern const char kAutofillNegativeUploadRate[];
 extern const char kAutofillPositiveUploadRate[];