[Autofill] Do not show Autocomplete suggestions for credit card fields.

components/autofill/core/browser/autofill_manager.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/autofill/core/browser/autofill_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 532 matching lines @@
         // TODO(mathp): Differentiate between number of suggestions available
         // (current metric) and number shown to the user.
         if (!has_logged_address_suggestions_count_ && !section_is_autofilled) {
           AutofillMetrics::LogAddressSuggestionsCount(suggestions.size());
           has_logged_address_suggestions_count_ = true;
         }
       }
     }
   }
 
-  if (suggestions.empty() && field.should_autocomplete) {
-    // Show autocomplete. Suggestions come back asynchronously, so the
-    // autocomplete manager will handle sending the results back to the
-    // renderer.
+  // If there are no Autofill suggestions, consider showing Autocomplete
+  // suggestions. We will not show Autocomplete suggestions for a field that
+  // specifies autocomplete=off or a field that we think is a credit card field.
+  if (suggestions.empty() && field.should_autocomplete &&
+      !(autofill_field &&
+        autofill_field->Type().group() == CREDIT_CARD)) {

[Justin Donnelly, 2016/04/26 21:19:00]

How about carving out an exception for Type() == CREDIT_CARD_NAME_FULL? That's
not sensitive and would be helpful when filling out a cc form without autofill.

[Mathieu, 2016/04/27 15:31:28]

Sure, I went with restricting the exclusion to CVC, number and expiration.

+    // Suggestions come back asynchronously, so the Autocomplete manager will
+    // handle sending the results back to the renderer.
     autocomplete_history_manager_->OnGetAutocompleteSuggestions(
         query_id, field.name, field.value, field.form_control_type);
     return;
   }
 
   // Send Autofill suggestions (could be an empty list).
   autocomplete_history_manager_->CancelPendingQuery();
   external_delegate_->OnSuggestionsReturned(query_id, suggestions);
 }
 
@@ skipping 1430 matching lines @@
     if (i > 0)
       fputs("Next oldest form:\n", file);
   }
   fputs("\n", file);
 
   fclose(file);
 }
 #endif  // ENABLE_FORM_DEBUG_DUMP
 
 }  // namespace autofill