Don't suggest autofill profiles that are subsets of other profiles.

components/autofill/core/browser/autofill_profile.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_profile.h"
 
 #include <algorithm>
 #include <functional>
 #include <map>
 #include <ostream>
@@ skipping 547 matching lines @@
   return !operator==(profile);
 }
 
 const base::string16 AutofillProfile::PrimaryValue() const {
   return GetRawInfo(ADDRESS_HOME_LINE1) + GetRawInfo(ADDRESS_HOME_CITY);
 }
 
 bool AutofillProfile::IsSubsetOf(const AutofillProfile& profile,
                                  const std::string& app_locale) const {
   ServerFieldTypeSet types;
-  GetNonEmptyTypes(app_locale, &types);
+  GetSupportedTypes(&types);
+  return IsSubsetOfForFieldSet(profile, app_locale, types);
+}
 
+bool AutofillProfile::IsSubsetOfForFieldSet(
+    const AutofillProfile& profile,
+    const std::string& app_locale,
+    const ServerFieldTypeSet& types) const {
   for (ServerFieldType type : types) {
+    base::string16 value = GetRawInfo(type);
+    if (value.empty())
+      continue;
+
     if (type == NAME_FULL || type == ADDRESS_HOME_STREET_ADDRESS) {
       // Ignore the compound "full name" field type.  We are only interested in
       // comparing the constituent parts.  For example, if |this| has a middle
       // name saved, but |profile| lacks one, |profile| could still be a subset
       // of |this|.  Likewise, ignore the compound "street address" type, as we
       // are only interested in matching line-by-line.
       continue;
     } else if (AutofillType(type).group() == PHONE_HOME) {
       // Phone numbers should be canonicalized prior to being compared.
       if (type != PHONE_HOME_WHOLE_NUMBER) {
         continue;
       } else if (!i18n::PhoneNumbersMatch(
-                     GetRawInfo(type), profile.GetRawInfo(type),
+                     value, profile.GetRawInfo(type),
                      base::UTF16ToASCII(GetRawInfo(ADDRESS_HOME_COUNTRY)),
                      app_locale)) {
         return false;
       }
-    } else if (base::StringToLowerASCII(GetRawInfo(type)) !=
+    } else if (base::StringToLowerASCII(value) !=
                base::StringToLowerASCII(profile.GetRawInfo(type))) {
       return false;
     }
   }
 
   return true;
 }
 
 void AutofillProfile::CopyAndUpdateNameList(
     const std::vector<base::string16> names,
@@ skipping 544 matching lines @@
       << UTF16ToUTF8(profile.GetRawInfo(ADDRESS_HOME_SORTING_CODE))
       << " "
       << UTF16ToUTF8(profile.GetRawInfo(ADDRESS_HOME_COUNTRY))
       << " "
       << profile.language_code()
       << " "
       << UTF16ToUTF8(MultiString(profile, PHONE_HOME_WHOLE_NUMBER));
 }
 
 }  // namespace autofill