Add an AutofillProfileComparator class.

components/autofill/core/browser/autofill_profile_comparator.h

Index: components/autofill/core/browser/autofill_profile_comparator.h
diff --git a/components/autofill/core/browser/autofill_profile_comparator.h b/components/autofill/core/browser/autofill_profile_comparator.h
new file mode 100644
index 0000000000000000000000000000000000000000..7664beb9f410435d77777a1d8e7df072ca606af5
--- /dev/null
+++ b/components/autofill/core/browser/autofill_profile_comparator.h
@@ -0,0 +1,131 @@
+// Copyright 2016 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_BROWSER_AUTOFILL_PROFILE_COMPARATOR_H_
+#define COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_PROFILE_COMPARATOR_H_
+
+#include <memory>
+#include <set>
+
+#include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
+#include "components/autofill/core/browser/autofill_profile.h"
+#include "components/autofill/core/common/autofill_l10n_util.h"
+#include "third_party/icu/source/i18n/unicode/translit.h"
+
+namespace autofill {
+
+// A utility class to assist in the comparison of AutofillProfile data.
+class AutofillProfileComparator {
+ public:
+  AutofillProfileComparator();
+  ~AutofillProfileComparator();
+
+  enum WhitespaceSpec { RETAIN_WHITESPACE, DISCARD_WHITESPACE };
+
+  // Returns a copy of |text| with uppercase converted to lowercase and
+  // diacritics removed.
+  //
+  // If |whitespace_spec| is RETAIN_WHITESPACE, punctuation is converted to
+  // spaces, and extraneous whitespace is trimmed and collapsed. For example,
+  // "Jean- François" becomes "jean francois".
+  //
+  // If |whitespace_spec| is DISCARD_WHITESPACE, punctuation and whitespace are
+  // discarded. For example, +1 (234) 567-8900 becomes 12345678900.
+  base::string16 NormalizeForComparison(
+      base::StringPiece16 text,
+      WhitespaceSpec whitespace_spec = RETAIN_WHITESPACE) const;
+
+  // Returns true if |p1| and |p2| are viable merge candidates. This means that
+  // their names, addresses, email addreses, company names, and phone numbers
+  // are all pairwise equivalent or mergeable.
+  bool IsMergeable(const AutofillProfile& p1, const AutofillProfile& p2) const;

[sebsg, 2016/06/08 19:03:54]

nit: AreMergeable?

[Roger McFarlane (Chromium), 2016/06/09 20:19:11]

Done.

+
+ protected:
+  // Returns the set of unique tokens in |s|. Note that the string data backing
+  // |s| is expected to have a lifetime which exceeds the call to UniqueTokens.
+  static std::set<base::StringPiece16> UniqueTokens(base::StringPiece16 s);
+
+  // Returns true if all of the tokens in |s1| are in |s2| or vice versa.
+  static bool HaveSameTokens(base::StringPiece16 s1, base::StringPiece16 s2);
+
+  // Generate the set of full/initial variants for |name|. For example, given
+  // "jean francois" (the normalized for comparison form of "Jean-François")
+  // this function returns the set:
+  //
+  //   { "", "f", "francois,
+  //     "j", "j f", "j francois",
+  //     "jean", "jean f", "jean francois" }
+  //
+  // Note: Expects that |name| is already normalized for comparison.
+  std::set<base::string16> GetNameVariants(const base::string16& name) const;
+
+  // Returns true of |full_name| is a variant of the full name in |profile|.

[sebsg, 2016/06/08 19:03:55]

nit: of -> if

[Roger McFarlane (Chromium), 2016/06/09 20:19:11]

Done.

+  //
+  // This function generates all variations of the full name for |profile| and
+  // returns true if one of these variants is equal to |full_name|. For example,
+  // this function will return true if |full_name| is "John Q. Public" and the
+  // name in |profile| is "John Quincy Public" because the name from |full_name|
+  // can be derived from |profile| by using the middle initial. Note that the
+  // reverse is not true, "John Quincy Public" is not a name variant of "John Q.
+  // Public".
+  //
+  // Note: Expects that |full_name| is already normalized for comparison.
+  bool IsNameVariantOf(const AutofillProfile& profile,
+                       const base::string16& full_name) const;
+
+  // Returns true if |p1| and |p2| have names which are equivalent for the
+  // purposes of merging the two profiles. This means one of the names is
+  // empty, the names are the same, or one name is a variation of the other.

[sebsg, 2016/06/08 19:03:55]

no modulo case?

[Roger McFarlane (Chromium), 2016/06/09 20:19:11]

all comparisons are performed post normalization. Added a comment to that
effect.

+  //
+  // Note that this method does not provide any guidance on actually merging
+  // the names.
+  bool HaveMergeableNames(const AutofillProfile& p1,
+                          const AutofillProfile& p2) const;
+
+  // Returns true if |p1| and |p2| have email addresses which are equivalent for
+  // the purposes of merging the two profiles. This means one of the email
+  // addresses is empty, or the email addresses are the same (modulo case).
+  //
+  // Note that this method does not provide any guidance on actually merging
+  // the email addresses.
+  bool HaveMergeableEmailAddresses(const AutofillProfile& p1,
+                                   const AutofillProfile& p2) const;
+
+  // Returns true if |p1| and |p2| have company names which are equivalent for
+  // the purposes of merging the two profiles. This means one of the company
+  // names is empty, or the normalized company names are the same (modulo case).
+  //
+  // Note that this method does not provide any guidance on actually merging
+  // the company names.
+  bool HaveMergeableCompanyNames(const AutofillProfile& p1,
+                                 const AutofillProfile& p2) const;
+
+  // Returns true if |p1| and |p2| have phone numbers which are equivalent for
+  // the purposes of merging the two profiles. This means one of the phone
+  // numbers is empty, or the phone names are the same.

[sebsg, 2016/06/08 19:03:55]

... phone names -> phone numbers. 

Also from the description I'm not sure if

(123) 123-1234
and
1231231234

would be considered mergeable? Could we add normalized if this is the case?

[Roger McFarlane (Chromium), 2016/06/09 20:19:11]

Done.

+  //
+  // Note that this method does not provide any guidance on actually merging
+  // the company names.
+  bool HaveMergeablePhoneNumbers(const AutofillProfile& p1,
+                                 const AutofillProfile& p2) const;
+
+  // Returns true if |p1| and |p2| have addresses which are equivalent for the
+  // purposes of merging the two profiles. This means one of the addresses is
+  // empty, or the addresses are a match. This uses a number of normalization
+  // and comparison heuristics to determine if to addresses match.

[sebsg, 2016/06/08 19:03:54]

nit: ... if to addresses -> ... if two addresses

[Roger McFarlane (Chromium), 2016/06/09 20:19:11]

Done.

+  //
+  // Note that this method does not provide any guidance on actually merging
+  // the email addresses.
+  bool HaveMergeableAddresses(const AutofillProfile& p1,
+                              const AutofillProfile& p2) const;
+
+ private:
+  l10n::CaseInsensitiveCompare case_insensitive_compare_;
+  std::unique_ptr<icu::Transliterator> transliterator_;
+};
+
+}  // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_PROFILE_COMPARATOR_H_