[Autofill] Use string pieces instead of strings for regexes.

This CL migrates the input and pattern base::string16 of
autofill::MatchPattern() to base::StringPiece16.

Bug: 1007974
Change-Id: I6c5c1b21ad39bc6317bbc51e1e5c3c4b24455aee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628289
Commit-Queue: Matthias Körber <koerber@google.com>
Auto-Submit: Christoph Schwering <schwering@google.com>
Reviewed-by: Matthias Körber <koerber@google.com>
Cr-Commit-Position: refs/heads/master@{#844044}

components/autofill/core/browser/autofill_regexes.cc

@@ -4,8 +4,8 @@
 
 #include "components/autofill/core/browser/autofill_regexes.h"
 
+#include <map>
 #include <memory>
-#include <unordered_map>
 #include <utility>
 
 #include "base/check.h"
@@ -28,19 +28,20 @@ class AutofillRegexes {
   AutofillRegexes() = default;
 
   // Returns the compiled regex matcher corresponding to |pattern|.
-  icu::RegexMatcher* GetMatcher(const base::string16& pattern);
+  icu::RegexMatcher* GetMatcher(const base::StringPiece16& pattern);
 
  private:
   ~AutofillRegexes() = default;
 
   // Maps patterns to their corresponding regex matchers.
-  std::unordered_map<base::string16, std::unique_ptr<icu::RegexMatcher>>
+  std::map<base::string16, std::unique_ptr<icu::RegexMatcher>, std::less<>>
       matchers_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillRegexes);
 };
 
-icu::RegexMatcher* AutofillRegexes::GetMatcher(const base::string16& pattern) {
+icu::RegexMatcher* AutofillRegexes::GetMatcher(
+    const base::StringPiece16& pattern) {
   auto it = matchers_.find(pattern);
   if (it == matchers_.end()) {
     const icu::UnicodeString icu_pattern(false, pattern.data(),
@@ -62,8 +63,8 @@ icu::RegexMatcher* AutofillRegexes::GetMatcher(const base::string16& pattern) {
 
 namespace autofill {
 
-bool MatchesPattern(const base::string16& input,
-                    const base::string16& pattern,
+bool MatchesPattern(const base::StringPiece16& input,
+                    const base::StringPiece16& pattern,
                     base::string16* match,
                     int32_t group_to_be_captured) {
   static base::NoDestructor<AutofillRegexes> g_autofill_regexes;

components/autofill/core/browser/autofill_regexes.h

@@ -6,6 +6,7 @@
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_REGEXES_H_
 
 #include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
 
 // Parsing utilities.
 namespace autofill {
@@ -13,8 +14,8 @@ namespace autofill {
 // Case-insensitive regular expression matching.
 // Returns true if |pattern| is found in |input|.
 // The |group_to_be_captured| numbered group is captured into |match|.
-bool MatchesPattern(const base::string16& input,
-                    const base::string16& pattern,
+bool MatchesPattern(const base::StringPiece16& input,
+                    const base::StringPiece16& pattern,
                     base::string16* match = nullptr,
                     int32_t group_to_be_captured = 0);