Change uses of base::JoinString to pass StringPieces where possible.

extensions/common/permissions/socket_permission_entry.cc

 // Copyright 2014 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 "extensions/common/permissions/socket_permission_entry.h"
 
 #include <stdint.h>
 
 #include <cstdlib>
 #include <memory>
 #include <sstream>
 #include <tuple>
 #include <vector>
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "extensions/common/permissions/api_permission.h"
 #include "extensions/common/permissions/socket_permission.h"
 #include "url/url_canon.h"
 
 namespace {
 
 using content::SocketPermissionRequest;
 
@@ skipping 124 matching lines @@
   if (!result.IsAddressBoundType())
     return false;
 
   result.pattern_.host = pattern_tokens[0];
   if (!result.pattern_.host.empty()) {
     if (StartsOrEndsWithWhitespace(result.pattern_.host))
       return false;
     result.pattern_.host = base::ToLowerASCII(result.pattern_.host);
 
     // The first component can optionally be '*' to match all subdomains.
-    std::vector<std::string> host_components =
-        base::SplitString(result.pattern_.host, std::string(1, kDot),
-                          base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
+    std::vector<base::StringPiece> host_components =
+        base::SplitStringPiece(result.pattern_.host, std::string{kDot},
+                               base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
     DCHECK(!host_components.empty());
 
     if (host_components[0] == kWildcard || host_components[0].empty()) {
       host_components.erase(host_components.begin(),
                             host_components.begin() + 1);
     } else {
       result.match_subdomains_ = false;
     }
     result.pattern_.host = base::JoinString(host_components, ".");
   }
@@ skipping 32 matching lines @@
 
   if (pattern_.port == kWildcardPortNumber)
     result.append(1, kColon).append(kWildcard);
   else
     result.append(1, kColon).append(base::UintToString(pattern_.port));
 
   return result;
 }
 
 }  // namespace extensions