mac: Only show the access Address Book prompt a fixed number of times.

components/autofill/core/common/autofill_pref_names.cc

Index: components/autofill/core/common/autofill_pref_names.cc
diff --git a/components/autofill/core/common/autofill_pref_names.cc b/components/autofill/core/common/autofill_pref_names.cc
index f35cb77586d5f50a1eae279a1d747285019207ea..829d5e7c15fe43046fbb1c0e319c17d2660f7115 100644
--- a/components/autofill/core/common/autofill_pref_names.cc
+++ b/components/autofill/core/common/autofill_pref_names.cc
@@ -22,6 +22,12 @@ const char kAutofillEnabled[] = "autofill.enabled";
 const char kAutofillMacAddressBookQueried[] =
     "autofill.auxiliary_profiles_queried";
 
+// The number of times that the access Address Book prompt has been shown. It
+// will only show for a fixed number of instances, and then it will stop
+// showing.
+const char kAutofillMacAddressBookShowedCount[] =
+    "autofill.mac_address_book_prompt_showed_count";
+
 // Double that indicates negative (for not matched forms) upload rate.
 const char kAutofillNegativeUploadRate[] = "autofill.negative_upload_rate";