[Autofill/Autocomplete Feature] Substring matching instead of prefix matching.

components/autofill/core/browser/personal_data_manager.cc

Index: components/autofill/core/browser/personal_data_manager.cc
diff --git a/components/autofill/core/browser/personal_data_manager.cc b/components/autofill/core/browser/personal_data_manager.cc
index ca41fd5b5cf8a22f8287fdc02fb3bdc74b62855d..e99118217db1896f69795c4a3da680015e1d00af 100644
--- a/components/autofill/core/browser/personal_data_manager.cc
+++ b/components/autofill/core/browser/personal_data_manager.cc
@@ -30,6 +30,7 @@
 #include "components/autofill/core/browser/validation.h"
 #include "components/autofill/core/common/autofill_pref_names.h"
 #include "components/autofill/core/common/autofill_switches.h"
+#include "components/autofill/core/common/autofill_util.h"
 #include "components/signin/core/browser/account_tracker_service.h"
 #include "components/signin/core/common/signin_pref_names.h"
 #include "third_party/libaddressinput/src/cpp/include/libaddressinput/address_data.h"
@@ -795,14 +796,32 @@ std::vector<Suggestion> PersonalDataManager::GetProfileSuggestions(
       continue;
     base::string16 value_canon =
         AutofillProfile::CanonicalizeProfileString(value);
-    if (base::StartsWith(value_canon, field_contents_canon, true)) {
-      // Prefix match, add suggestion.
+    // CanonicalizeProfileString() returns lower-case string with all

[please use gerrit instead, 2015/06/29 22:06:29]

CanonicalizeProfileString() does not replace "all separators". Please correct
your comment.

[Pritam Nikam, 2015/06/30 15:05:50]

Done.

I reffered it from here [1]. 

[1].
https://code.google.com/p/chromium/codesearch#chromium/src/components/autofil...

Rephrased it to:

// CanonicalizeProfileString() returns lower-case string with separators;
// includes space, line and paragraph along with punctuations like dash,
// start, end and others {U_DASH_PUNCTUATION, U_START_PUNCTUATION,
// U_END_PUNCTUATION, U_CONNECTOR_PUNCTUATION, U_OTHER_PUNCTUATION,
// U_SPACE_SEPARATOR, U_LINE_SEPARATOR, U_PARAGRAPH_SEPARATOR}; substituted
// by whitespaces and trims off trailing whitespace if any. Passing
// |value_canon| and |field_contents_canon| to ContainsTokenThatStartsWith()
// may lead to unexpected result, hence preferred passing |value| and
// |field_contents| instead.

+    // separator substituted by whitespaces and trims off trailing whitespace
+    // if any. Passing |value_canon| and |field_contents_canon| to
+    // ContainsTokenThatStartsWith() may lead to unexpected result, hence
+    // preferred passing |values[i]| and |field_contents| instead.

[please use gerrit instead, 2015/06/29 22:06:29]

This part of the comment is outdated. There's no values[i] anywhere in this
file.

[Pritam Nikam, 2015/06/30 15:05:50]

Done.

+    bool substring_matched_suggestion = false;
+    if (base::StartsWith(value_canon, field_contents_canon, true) ||
+        (substring_matched_suggestion =
+             ContainsTokenThatStartsWith(value, field_contents, false))) {

[please use gerrit instead, 2015/06/29 22:06:29]

It's rare in Chromium code to assign a variable inside of an if clause. Is there
a simpler way to write this without such assignment?

[Pritam Nikam, 2015/06/30 15:05:50]

Done.

Changes to:
   
   bool prefix_matched_suggestion = base::StartsWith(...);
   if (prefix_matched_suggestion || ContainsTokenThatStartsWith(...)) {
     ...
     suggestions.back().match = prefix_matched_suggestion
                                    ? Suggestion::PREFIX_MATCH
                                    : Suggestion::SUBSTRING_MATCH;
   }

[please use gerrit instead, 2015/06/30 19:06:22]

Nice.

       matched_profiles.push_back(profile);
       suggestions.push_back(Suggestion(value));
       suggestions.back().backend_id = profile->guid();
+      suggestions.back().match = substring_matched_suggestion
+                                     ? Suggestion::SUBSTRING_MATCH
+                                     : Suggestion::PREFIX_MATCH;
     }
   }
 
+  // Prefix matches should precede other token matches.
+  if (IsFeatureSubstringMatchEnabled()) {
+    std::stable_sort(suggestions.begin(), suggestions.end(),
+                     [](const Suggestion& a, const Suggestion& b) {
+                       return a.match < b.match;
+                     });

[please use gerrit instead, 2015/06/29 22:06:29]

Is this clang formatted?

[Pritam Nikam, 2015/06/30 15:05:50]

Yes.

+  }
+
   // Don't show two suggestions if one is a subset of the other.
   std::vector<AutofillProfile*> unique_matched_profiles;
   std::vector<Suggestion> unique_suggestions;
@@ -854,6 +873,7 @@ std::vector<Suggestion> PersonalDataManager::GetCreditCardSuggestions(
     return std::vector<Suggestion>();
 
   std::list<const CreditCard*> cards_to_suggest;
+  std::list<const CreditCard*> substring_matched_suggestions;

[please use gerrit instead, 2015/06/29 22:06:29]

s/substring_matched_suggestions/substring_matched_cards

[Pritam Nikam, 2015/06/30 15:05:50]

Done.

   for (const CreditCard* credit_card : GetCreditCards()) {
     // The value of the stored data for this field type in the |credit_card|.
     base::string16 creditcard_field_value =
@@ -872,12 +892,24 @@ std::vector<Suggestion> PersonalDataManager::GetCreditCardSuggestions(
            field_contents.size() >= 6)) {
         continue;
       }
-    } else if (!base::StartsWith(creditcard_field_value, field_contents,
-                                 false)) {
-      continue;
+      cards_to_suggest.push_back(credit_card);
+    } else if (base::StartsWith(creditcard_field_value, field_contents,
+                                false)) {
+      cards_to_suggest.push_back(credit_card);
+    } else if (ContainsTokenThatStartsWith(creditcard_field_value,
+                                           field_contents, false)) {
+      substring_matched_suggestions.push_back(credit_card);
     }
+  }
 
-    cards_to_suggest.push_back(credit_card);
+  cards_to_suggest.sort(RankByMfu);
+
+  // Prefix matches should precede other token matches.
+  if (IsFeatureSubstringMatchEnabled()) {
+    substring_matched_suggestions.sort(RankByMfu);
+    cards_to_suggest.insert(cards_to_suggest.end(),
+                            substring_matched_suggestions.begin(),
+                            substring_matched_suggestions.end());
   }
 
   // De-dupe card suggestions. Full server cards shadow local cards, and
@@ -905,8 +937,6 @@ std::vector<Suggestion> PersonalDataManager::GetCreditCardSuggestions(
     }
   }
 
-  cards_to_suggest.sort(RankByMfu);
-
   std::vector<Suggestion> suggestions;
   for (const CreditCard* credit_card : cards_to_suggest) {
     // Make a new suggestion.