Revert of Limit form-less Autofilling to pages that look like checkout pages.

components/autofill/core/browser/autofill_regexes.cc

Index: components/autofill/core/browser/autofill_regexes.cc
diff --git a/components/autofill/core/browser/autofill_regexes.cc b/components/autofill/core/browser/autofill_regexes.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bd5c0e9427638ad14b6bf420a8d402989c5cb96e
--- /dev/null
+++ b/components/autofill/core/browser/autofill_regexes.cc
@@ -0,0 +1,80 @@
+// Copyright 2013 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/autofill_regexes.h"
+
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "base/strings/string16.h"
+#include "third_party/icu/source/i18n/unicode/regex.h"
+
+namespace {
+
+// A singleton class that serves as a cache of compiled regex patterns.
+class AutofillRegexes {
+ public:
+  static AutofillRegexes* GetInstance();
+
+  // Returns the compiled regex matcher corresponding to |pattern|.
+  icu::RegexMatcher* GetMatcher(const base::string16& pattern);
+
+ private:
+  AutofillRegexes();
+  ~AutofillRegexes();
+  friend struct DefaultSingletonTraits<AutofillRegexes>;
+
+  // Maps patterns to their corresponding regex matchers.
+  base::ScopedPtrHashMap<base::string16, icu::RegexMatcher> matchers_;
+
+  DISALLOW_COPY_AND_ASSIGN(AutofillRegexes);
+};
+
+// static
+AutofillRegexes* AutofillRegexes::GetInstance() {
+  return Singleton<AutofillRegexes>::get();
+}
+
+AutofillRegexes::AutofillRegexes() {
+}
+
+AutofillRegexes::~AutofillRegexes() {
+}
+
+icu::RegexMatcher* AutofillRegexes::GetMatcher(const base::string16& pattern) {
+  auto it = matchers_.find(pattern);
+  if (it == matchers_.end()) {
+    const icu::UnicodeString icu_pattern(pattern.data(), pattern.length());
+
+    UErrorCode status = U_ZERO_ERROR;
+    scoped_ptr<icu::RegexMatcher> matcher(
+        new icu::RegexMatcher(icu_pattern, UREGEX_CASE_INSENSITIVE, status));
+    DCHECK(U_SUCCESS(status));
+
+    auto result = matchers_.add(pattern, matcher.Pass());
+    DCHECK(result.second);
+    it = result.first;
+  }
+  return it->second;
+}
+
+}  // namespace
+
+namespace autofill {
+
+bool MatchesPattern(const base::string16& input,
+                    const base::string16& pattern) {
+  icu::RegexMatcher* matcher =
+      AutofillRegexes::GetInstance()->GetMatcher(pattern);
+  icu::UnicodeString icu_input(input.data(), input.length());
+  matcher->reset(icu_input);
+
+  UErrorCode status = U_ZERO_ERROR;
+  UBool match = matcher->find(0, status);
+  DCHECK(U_SUCCESS(status));
+  return match == TRUE;
+}
+
+}  // namespace autofill