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

remoting/base/capabilities.cc

 // 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 "remoting/base/capabilities.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/stl_util.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 
 namespace remoting {
 
 bool HasCapability(const std::string& capabilities, const std::string& key) {
   std::vector<base::StringPiece> caps = base::SplitStringPiece(
       capabilities, " ", base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
   return std::find(caps.begin(), caps.end(), base::StringPiece(key)) !=
          caps.end();
 }
 
 std::string IntersectCapabilities(const std::string& client_capabilities,
                                   const std::string& host_capabilities) {
-  std::vector<std::string> client_caps = base::SplitString(
-      client_capabilities, " ", base::KEEP_WHITESPACE,
-      base::SPLIT_WANT_NONEMPTY);
+  std::vector<base::StringPiece> client_caps =
+      base::SplitStringPiece(client_capabilities, " ", base::KEEP_WHITESPACE,
+                             base::SPLIT_WANT_NONEMPTY);
   std::sort(client_caps.begin(), client_caps.end());
 
-  std::vector<std::string> host_caps = base::SplitString(
-        host_capabilities, " ", base::KEEP_WHITESPACE,
-        base::SPLIT_WANT_NONEMPTY);
+  std::vector<base::StringPiece> host_caps = base::SplitStringPiece(
+      host_capabilities, " ", base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
   std::sort(host_caps.begin(), host_caps.end());
 
-  std::vector<std::string> result =
-      base::STLSetIntersection<std::vector<std::string> >(
-          client_caps, host_caps);
+  std::vector<base::StringPiece> result =
+      base::STLSetIntersection<std::vector<base::StringPiece>>(client_caps,
+                                                               host_caps);
 
   return base::JoinString(result, " ");
 }
 
 }  // namespace remoting