[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 {
+
+enum CaseSensitivity {
+  CASE_SENSITIVE,  // for case sensitive match;
+  CASE_IGNORE      // for case insensitive match;
+};
+
+// Returns |true| when command line switch
+// |kEnableSuggestionsWithSubstringMatch| is on; otherwise |false|.
+bool IsFeatureSubstringMatchEnabled();
+
+// Splits |field_suggestion| into tokens, separated by characters from " .,-_@".
+// Returns true if |field_content| is a prefix of some token; otherwise false.
+bool IsContentsPrefixOfSuggestionToken(const base::string16& field_suggestion,
+                                       const base::string16& field_contents,
+                                       CaseSensitivity case_sensitivity);
+
+// Returns |field_contents|'s offset within the |field_suggestion| on successful
+// match and compute the selection range's |start| and |end| indices; otherwise
+// returns |base::string16::npos|.
+base::string16::size_type ComputeRange(const base::string16& field_suggestion,
+                                       const base::string16& field_contents,
+                                       size_t* start,
+                                       size_t* end);
+
+}  // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_UTIL_H_