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

components/autofill/core/common/autofill_util.h

+// Copyright 2015 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 COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_UTIL_H_
+#define COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_UTIL_H_
+
+#include "base/strings/string16.h"
+
+namespace autofill {
+
+// Returns true when command line switch |kEnableSuggestionsWithSubstringMatch|
+// is on.
+bool IsFeatureSubstringMatchEnabled();
+
+// Returns true if the |field_contents| prefixes any of the |suggestion| tokens

[vabr (Chromium), 2015/07/09 06:17:52]

The comment is not correct. This is not about prefixing tokens, this is about
substrings starting at token boundaries. To illustrate for a suggestion "a.b.c"
and field contents "b.c", the function returns true, but according to the
comment it should return false, because "b.c" is not a prefix of any of the 3
tokens "a", "b", and "c".
Please correct the comment (also for the method below).

Subsequently the name of the method is also incorrect. What about
FieldIsSuggestionSubstringStartingOnTokenBoundary? It is long, but it is
correct. Feel free to come up with different names, but make sure they are
correct.

[Pritam Nikam, 2015/07/10 16:58:46]

Done.

+// separated by characters " .,-_@".
+bool ContainsTokenThatStartsWith(const base::string16& suggestion,
+                                 const base::string16& field_contents,
+                                 bool case_sensitive);
+
+// Finds if the |field_contents| prefixes any of the |suggestion| tokens,
+// separated by characters " .,-_@". Returns the start position of the text

[vabr (Chromium), 2015/07/09 06:17:52]

nit: Please clarify:
Returns the start position -> Returns what should be the start position

[Pritam Nikam, 2015/07/10 16:58:46]

Done.

+// selection in the field; base::string16::npos otherwise. "preview-on-hover"
+// feature is one such use case where |field_contents| may not match
+// |suggestion|.
+size_t GetTextSelectionStart(const base::string16& suggestion,
+                             const base::string16& field_contents,
+                             bool case_sensitive);
+
+}  // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_UTIL_H_