[Autofill] Moved BorrowedTransliterator in its own file

This is needed to make the transliteration accessible to the merging
logic of structured address components.

Change-Id: I52738045df1d7b0b84e71adbfc5baf7f90cadf37
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2332628
Commit-Queue: Matthias Körber <koerber@google.com>
Reviewed-by: Christoph Schwering <schwering@google.com>
Cr-Commit-Position: refs/heads/master@{#794312}

components/autofill/core/browser/BUILD.gn

@@ -98,6 +98,8 @@ jumbo_static_library("browser") {
     "data_model/autofill_structured_address_regex_provider.h",
     "data_model/autofill_structured_address_utils.cc",
     "data_model/autofill_structured_address_utils.h",
+    "data_model/borrowed_transliterator.cc",
+    "data_model/borrowed_transliterator.h",
     "data_model/contact_info.cc",
     "data_model/contact_info.h",
     "data_model/credit_card.cc",
@@ -583,6 +585,7 @@ source_set("unit_tests") {
     "data_model/autofill_structured_address_name_unittest.cc",
     "data_model/autofill_structured_address_regex_provider_unittest.cc",
     "data_model/autofill_structured_address_utils_unittest.cc",
+    "data_model/borrowed_transliterator_unittest.cc",
     "data_model/contact_info_unittest.cc",
     "data_model/credit_card_unittest.cc",
     "data_model/phone_number_unittest.cc",

components/autofill/core/browser/data_model/autofill_profile_comparator.cc

@@ -10,20 +10,16 @@
 #include "base/i18n/case_conversion.h"
 #include "base/i18n/char_iterator.h"
 #include "base/i18n/unicodestring.h"
-#include "base/no_destructor.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversion_utils.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/synchronization/lock.h"
 #include "components/autofill/core/browser/address_rewriter.h"
 #include "components/autofill/core/browser/autofill_data_util.h"
 #include "components/autofill/core/browser/autofill_metrics.h"
 #include "components/autofill/core/browser/geo/autofill_country.h"
 #include "components/autofill/core/browser/geo/state_names.h"
 #include "components/autofill/core/common/autofill_clock.h"
-#include "third_party/icu/source/common/unicode/unistr.h"
-#include "third_party/icu/source/i18n/unicode/translit.h"
 #include "third_party/libphonenumber/phonenumber_api.h"
 
 using base::UTF16ToUTF8;
@@ -190,51 +186,6 @@ int32_t NormalizingIterator::GetNextChar() {
   return iter_.get();
 }
 
-// This RAII class provides a thread-safe interface to a shared transliterator.
-// Sharing a single transliterator is advisable due its high construction cost.
-class BorrowedTransliterator {
- public:
-  BorrowedTransliterator() : auto_lock_(GetLock()) {}
-
-  void Transliterate(icu::UnicodeString* text) const {
-    if (GetTransliterator() != nullptr) {
-      GetTransliterator()->transliterate(*text);
-    } else {
-      *text = text->toLower();
-    }
-  }
-
- private:
-  static base::Lock& GetLock() {
-    static base::NoDestructor<base::Lock> instance;
-    return *instance;
-  }
-
-  // Use ICU transliteration to remove diacritics and fold case.
-  // See http://userguide.icu-project.org/transforms/general
-  static std::unique_ptr<icu::Transliterator> CreateTransliterator() {
-    UErrorCode status = U_ZERO_ERROR;
-    std::unique_ptr<icu::Transliterator> transliterator(
-        icu::Transliterator::createInstance(
-            "NFD; [:Nonspacing Mark:] Remove; Lower; NFC", UTRANS_FORWARD,
-            status));
-    if (U_FAILURE(status) || transliterator == nullptr) {
-      // TODO(rogerm): Add a histogram to count how often this happens.
-      LOG(ERROR) << "Failed to create ICU Transliterator: "
-                 << u_errorName(status);
-    }
-    return transliterator;
-  }
-
-  static std::unique_ptr<icu::Transliterator>& GetTransliterator() {
-    static base::NoDestructor<std::unique_ptr<icu::Transliterator>> instance(
-        CreateTransliterator());
-    return *instance;
-  }
-
-  base::AutoLock auto_lock_;
-};
-
 }  // namespace
 
 AutofillProfileComparator::AutofillProfileComparator(
@@ -327,9 +278,7 @@ base::string16 AutofillProfileComparator::NormalizeForComparison(
   if (previous_was_whitespace && !result.empty())
     result.resize(result.size() - 1);
 
-  icu::UnicodeString value = icu::UnicodeString(result.data(), result.length());
-  BorrowedTransliterator().Transliterate(&value);
-  return base::i18n::UnicodeStringToString16(value);
+  return RemoveDiacriticsAndConvertToLowerCase(result);
 }
 
 bool AutofillProfileComparator::AreMergeable(const AutofillProfile& p1,

components/autofill/core/browser/data_model/autofill_profile_comparator.h

@@ -12,6 +12,7 @@
 #include "base/strings/string_piece.h"
 #include "components/autofill/core/browser/data_model/address.h"
 #include "components/autofill/core/browser/data_model/autofill_profile.h"
+#include "components/autofill/core/browser/data_model/borrowed_transliterator.h"
 #include "components/autofill/core/browser/data_model/contact_info.h"
 #include "components/autofill/core/common/autofill_l10n_util.h"
 

components/autofill/core/browser/data_model/borrowed_transliterator.cc

+// Copyright 2020 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/data_model/borrowed_transliterator.h"
+
+#include "base/logging.h"
+
+namespace autofill {
+
+BorrowedTransliterator::BorrowedTransliterator() : auto_lock_(GetLock()) {}
+
+BorrowedTransliterator::~BorrowedTransliterator() = default;
+
+void BorrowedTransliterator::Transliterate(icu::UnicodeString* text) const {
+  if (GetTransliterator() != nullptr) {
+    GetTransliterator()->transliterate(*text);
+  } else {
+    *text = text->toLower();
+  }
+}
+
+// static
+base::Lock& BorrowedTransliterator::GetLock() {
+  static base::NoDestructor<base::Lock> instance;
+  return *instance;
+}
+
+// static
+std::unique_ptr<icu::Transliterator>
+BorrowedTransliterator::CreateTransliterator() {
+  UErrorCode status = U_ZERO_ERROR;
+  std::unique_ptr<icu::Transliterator> transliterator(
+      icu::Transliterator::createInstance(
+          "NFD; [:Nonspacing Mark:] Remove; Lower; NFC", UTRANS_FORWARD,
+          status));
+  if (U_FAILURE(status) || transliterator == nullptr) {
+    // TODO(rogerm): Add a histogram to count how often this happens.
+    LOG(ERROR) << "Failed to create ICU Transliterator: "
+               << u_errorName(status);
+  }
+  return transliterator;
+}
+
+// static
+std::unique_ptr<icu::Transliterator>&
+BorrowedTransliterator::GetTransliterator() {
+  static base::NoDestructor<std::unique_ptr<icu::Transliterator>> instance(
+      CreateTransliterator());
+  return *instance;
+}
+
+base::string16 RemoveDiacriticsAndConvertToLowerCase(
+    base::StringPiece16 value) {
+  icu::UnicodeString result = icu::UnicodeString(value.data(), value.length());
+  BorrowedTransliterator().Transliterate(&result);
+  return base::i18n::UnicodeStringToString16(result);
+}
+
+}  // namespace autofill

components/autofill/core/browser/data_model/borrowed_transliterator.h

+// Copyright 2020 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_DATA_MODEL_BORROWED_TRANSLITERATOR_H_
+#define COMPONENTS_AUTOFILL_CORE_BROWSER_DATA_MODEL_BORROWED_TRANSLITERATOR_H_
+
+#include "base/i18n/unicodestring.h"
+#include "base/no_destructor.h"
+#include "base/synchronization/lock.h"
+#include "third_party/icu/source/common/unicode/unistr.h"
+#include "third_party/icu/source/i18n/unicode/translit.h"
+
+namespace autofill {
+
+// This RAII class provides a thread-safe interface to a shared transliterator.
+// Sharing a single transliterator is advisable due its high construction cost.
+class BorrowedTransliterator {
+ public:
+  BorrowedTransliterator();
+  virtual ~BorrowedTransliterator();
+
+  void Transliterate(icu::UnicodeString* text) const;
+
+ private:
+  static base::Lock& GetLock();
+
+  // Use ICU transliteration to remove diacritics and fold case.
+  // See http://userguide.icu-project.org/transforms/general
+  static std::unique_ptr<icu::Transliterator> CreateTransliterator();
+
+  static std::unique_ptr<icu::Transliterator>& GetTransliterator();
+
+  base::AutoLock auto_lock_;
+};
+
+// Apply the transliteration to a full string to convert it to lower case and to
+// remove the diacritics.
+// and remove the diacritics.
+base::string16 RemoveDiacriticsAndConvertToLowerCase(base::StringPiece16 value);
+
+}  // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_DATA_MODEL_BORROWED_TRANSLITERATOR_H_

components/autofill/core/browser/data_model/borrowed_transliterator_unittest.cc

+// Copyright 2020 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/data_model/borrowed_transliterator.h"
+
+#include "base/strings/string_piece.h"
+
+#include "base/strings/utf_string_conversions.h"
+#include "base/test/gtest_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace autofill {
+
+TEST(BorrowedTransliterator, RemoveDiacriticsAndConvertToLowerCase) {
+  EXPECT_EQ(RemoveDiacriticsAndConvertToLowerCase(
+                base::UTF8ToUTF16("āēaa11.īūčģķļņšžKāäǟḑēīļņōȯȱõȭŗšțūž")),
+            base::ASCIIToUTF16("aeaa11.iucgklnszkaaadeilnooooorstuz"));
+}
+
+}  // namespace autofill