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

components/task_scheduler_util/common/variations_util.cc

 // Copyright 2016 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/task_scheduler_util/common/variations_util.h"
 
 #include "base/command_line.h"
 #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 "base/task_scheduler/initialization_util.h"
 #include "base/time/time.h"
 #include "components/variations/variations_associated_data.h"
 
 namespace task_scheduler_util {
 
 namespace {
 
@@ skipping 105 matching lines @@
 
 #if !defined(OS_IOS)
 void AddVariationParamsToCommandLine(base::StringPiece key_prefix,
                                      base::CommandLine* command_line) {
   DCHECK(command_line);
 
   std::map<std::string, std::string> variation_params;
   if (!variations::GetVariationParams("BrowserScheduler", &variation_params))
     return;
 
-  std::vector<std::string> parts;
+  std::vector<base::StringPiece> parts;
   for (const auto& key_value : variation_params) {
     if (base::StartsWith(key_value.first, key_prefix,
                          base::CompareCase::SENSITIVE)) {
       if (ContainsSeparator(key_value.first) ||
           ContainsSeparator(key_value.second)) {
         DLOG(ERROR)
             << "Unexpected Character in Task Scheduler Variation Params: "
             << key_value.first << " [" << key_value.second << "]";
         return;
       }
@@ skipping 24 matching lines @@
       return std::map<std::string, std::string>();
     }
     base::StringPiece value = *it;
     variation_params[key.as_string()] = value.as_string();
   }
   return variation_params;
 }
 #endif  // !defined(OS_IOS)
 
 }  // namespace task_scheduler_util