Autofill Credit Card Signin Promo: Put behind Feature

components/autofill/core/browser/autofill_manager.cc

Index: components/autofill/core/browser/autofill_manager.cc
diff --git a/components/autofill/core/browser/autofill_manager.cc b/components/autofill/core/browser/autofill_manager.cc
index 04650708eb405ab020c84a21e309541af5932329..45bc868b8bbceebd0a3ff27f6e31bd648e6eca89 100644
--- a/components/autofill/core/browser/autofill_manager.cc
+++ b/components/autofill/core/browser/autofill_manager.cc
@@ -222,6 +222,10 @@ AutofillManager::~AutofillManager() {}
 // static
 void AutofillManager::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
+  // This pref is not synced because it's for a signin promo, which by
+  // definition will not be synced.
+  registry->RegisterIntegerPref(
+      prefs::kAutofillCreditCardSigninPromoImpressionCount, 0);
   registry->RegisterBooleanPref(
       prefs::kAutofillEnabled,
       true,
@@ -275,11 +279,30 @@ bool AutofillManager::ShouldShowScanCreditCard(const FormData& form,
 bool AutofillManager::ShouldShowCreditCardSigninPromo(
     const FormData& form,
     const FormFieldData& field) {
+  if (!IsAutofillCreditCardSigninPromoEnabled())
+    return false;
+
   // Check whether we are dealing with a credit card field and whether it's
   // appropriate to show the promo (e.g. the platform is supported).
   AutofillField* autofill_field = GetAutofillField(form, field);
-  return autofill_field && autofill_field->Type().group() == CREDIT_CARD &&
-         client_->ShouldShowSigninPromo();
+  if (!autofill_field || autofill_field->Type().group() != CREDIT_CARD ||
+      !client_->ShouldShowSigninPromo())
+    return false;
+
+  // The last step is checking if we are under the limit of impressions (a limit
+  // of 0 means there is no limit);
+  int impression_limit = GetCreditCardSigninPromoImpressionLimit();
+  int impression_count = client_->GetPrefs()->GetInteger(
+      prefs::kAutofillCreditCardSigninPromoImpressionCount);
+  if (impression_limit == 0 || impression_count < impression_limit) {
+    // The promo is guaranteed to be shown. Increment the impression count.

[sebsg, 2016/07/14 15:32:13]

Nit: I'm not sure about the phrasing. From what I understand, if we get here (in
the if) the promo will be shown but if we don't, the promo will never be shown. 

The word guaranteed makes me feel like the other way can sometime show the promo
too.

I'd replace by: The promo will be shown. Increment...

[Mathieu, 2016/07/14 21:51:44]

Done.

+    client_->GetPrefs()->SetInteger(
+        prefs::kAutofillCreditCardSigninPromoImpressionCount,
+        impression_count + 1);
+    return true;
+  }
+
+  return false;
 }
 
 void AutofillManager::OnFormsSeen(const std::vector<FormData>& forms,