Don't ask the browser for Autofill suggestions for non-autofillable form fields.

chrome/browser/autofill/autofill_manager.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_AUTOFILL_AUTOFILL_MANAGER_H_
 #define CHROME_BROWSER_AUTOFILL_AUTOFILL_MANAGER_H_
 #pragma once
 
 #include <list>
 #include <map>
@@ skipping 144 matching lines @@
   // updating the cache.  Returns false if the |form| is not autofillable, or if
   // it is not already present in the cache and the cache is full.
   bool GetCachedFormAndField(const webkit_glue::FormData& form,
                              const webkit_glue::FormField& field,
                              FormStructure** form_structure,
                              AutofillField** autofill_field) WARN_UNUSED_RESULT;
 
   // Re-parses |live_form| and adds the result to |form_structures_|.
   // |cached_form| should be a pointer to the existing version of the form, or
   // NULL if no cached version exists.  The updated form is then written into
-  // |updated_form|.
-  void UpdateCachedForm(const webkit_glue::FormData& live_form,
+  // |updated_form|.  Returns false if the cache could not be updated.
+  bool UpdateCachedForm(const webkit_glue::FormData& live_form,
                         const FormStructure* cached_form,
-                        FormStructure** updated_form);
+                        FormStructure** updated_form) WARN_UNUSED_RESULT;
 
   // Returns a list of values from the stored profiles that match |type| and the
   // value of |field| and returns the labels of the matching profiles. |labels|
   // is filled with the Profile label.
   void GetProfileSuggestions(FormStructure* form,
                              const webkit_glue::FormField& field,
                              AutofillFieldType type,
                              std::vector<string16>* values,
                              std::vector<string16>* labels,
                              std::vector<string16>* icons,
@@ skipping 131 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(AutofillMetricsTest, SaneMetricsWithCacheMismatch);
   FRIEND_TEST_ALL_PREFIXES(AutofillMetricsTest,
                            UserHappinessFormLoadAndSubmission);
   FRIEND_TEST_ALL_PREFIXES(AutofillMetricsTest, UserHappinessFormInteraction);
   FRIEND_TEST_ALL_PREFIXES(AutofillMetricsTest, FormFillDuration);
 
   DISALLOW_COPY_AND_ASSIGN(AutofillManager);
 };
 
 #endif  // CHROME_BROWSER_AUTOFILL_AUTOFILL_MANAGER_H_