[net/auth] Use StringPiece instead of constructing lots of strings.

R=mmenke@chromium.org

Bug: 927182
Change-Id: I610973df09e2fe1e370a4ca2b2c3ecc90af790c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1907150
Commit-Queue: Asanka Herath <asanka@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714338}

net/http/http_auth_challenge_tokenizer.h

@@ -7,6 +7,7 @@
 
 #include <string>
 
+#include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
 #include "net/http/http_util.h"
 
@@ -32,10 +33,8 @@ class NET_EXPORT_PRIVATE HttpAuthChallengeTokenizer {
   }
 
   // Get the auth scheme of the challenge.
-  std::string::const_iterator scheme_begin() const { return scheme_begin_; }
-  std::string::const_iterator scheme_end() const { return scheme_end_; }
-  std::string scheme() const {
-    return std::string(scheme_begin_, scheme_end_);
+  base::StringPiece scheme() const {
+    return base::StringPiece(scheme_begin_, scheme_end_);
   }
 
   std::string::const_iterator params_begin() const { return params_begin_; }

net/http/http_auth_handler_basic.h

@@ -46,7 +46,7 @@ class NET_EXPORT_PRIVATE HttpAuthHandlerBasic : public HttpAuthHandler {
       HttpAuthChallengeTokenizer* challenge) override;
 
  private:
-  ~HttpAuthHandlerBasic() override {}
+  ~HttpAuthHandlerBasic() override = default;
 
   bool ParseChallenge(HttpAuthChallengeTokenizer* challenge);
 };

net/http/http_auth_handler_factory.cc

@@ -200,7 +200,7 @@ int HttpAuthHandlerRegistryFactory::CreateAuthHandler(
     const NetLogWithSource& net_log,
     HostResolver* host_resolver,
     std::unique_ptr<HttpAuthHandler>* handler) {
-  std::string scheme = challenge->scheme();
+  auto scheme = challenge->scheme();
   if (scheme.empty()) {
     handler->reset();
     return ERR_INVALID_RESPONSE;

net/http/http_auth_multi_round_parse.cc

@@ -2,17 +2,19 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "net/http/http_auth_multi_round_parse.h"
+
 #include "base/base64.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "net/http/http_auth_challenge_tokenizer.h"
-#include "net/http/http_auth_multi_round_parse.h"
 
 namespace net {
 
 namespace {
 
 // Check that the scheme in the challenge matches the expected scheme
-bool SchemeIsValid(const std::string& scheme,
+bool SchemeIsValid(base::StringPiece scheme,
                    HttpAuthChallengeTokenizer* challenge) {
   // There is no guarantee that challenge->scheme() is valid ASCII, but
   // LowerCaseEqualsASCII will do the right thing even if it isn't.
@@ -23,7 +25,7 @@ bool SchemeIsValid(const std::string& scheme,
 }  // namespace
 
 HttpAuth::AuthorizationResult ParseFirstRoundChallenge(
-    const std::string& scheme,
+    base::StringPiece scheme,
     HttpAuthChallengeTokenizer* challenge) {
   // Verify the challenge's auth-scheme.
   if (!SchemeIsValid(scheme, challenge))
@@ -37,7 +39,7 @@ HttpAuth::AuthorizationResult ParseFirstRoundChallenge(
 }
 
 HttpAuth::AuthorizationResult ParseLaterRoundChallenge(
-    const std::string& scheme,
+    base::StringPiece scheme,
     HttpAuthChallengeTokenizer* challenge,
     std::string* encoded_token,
     std::string* decoded_token) {

net/http/http_auth_multi_round_parse.h

@@ -7,6 +7,7 @@
 
 #include <string>
 
+#include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
 #include "net/http/http_auth.h"
 
@@ -15,11 +16,11 @@ namespace net {
 class HttpAuthChallengeTokenizer;
 
 NET_EXPORT_PRIVATE HttpAuth::AuthorizationResult ParseFirstRoundChallenge(
-    const std::string& scheme,
+    base::StringPiece scheme,
     HttpAuthChallengeTokenizer* challenge);
 
 NET_EXPORT_PRIVATE HttpAuth::AuthorizationResult ParseLaterRoundChallenge(
-    const std::string& scheme,
+    base::StringPiece scheme,
     HttpAuthChallengeTokenizer* challenge,
     std::string* encoded_token,
     std::string* decoded_token);