Revert of Move JoinString to the base namespace

chrome/common/extensions/permissions/permission_set_unittest.cc

Index: chrome/common/extensions/permissions/permission_set_unittest.cc
diff --git a/chrome/common/extensions/permissions/permission_set_unittest.cc b/chrome/common/extensions/permissions/permission_set_unittest.cc
index 5070f17e7c2a3aae91affe42dae30cffd5277f87..e8a3f091928cd9e3c74bac9d7556ffe8b329c55c 100644
--- a/chrome/common/extensions/permissions/permission_set_unittest.cc
+++ b/chrome/common/extensions/permissions/permission_set_unittest.cc
@@ -69,14 +69,14 @@
   std::vector<std::string> strs;
   for (const PermissionMessage::ID& id : ids)
     strs.push_back(base::IntToString(id));
-  return base::StringPrintf("[ %s ]", base::JoinString(strs, ", ").c_str());
+  return base::StringPrintf("[ %s ]", JoinString(strs, ", ").c_str());
 }
 
 std::string PermissionIDsToString(const PermissionIDSet& ids) {
   std::vector<std::string> strs;
   for (const PermissionID& id : ids)
     strs.push_back(base::IntToString(id.id()));
-  return base::StringPrintf("[ %s ]", base::JoinString(strs, ", ").c_str());
+  return base::StringPrintf("[ %s ]", JoinString(strs, ", ").c_str());
 }
 
 std::string CoalescedPermissionIDsToString(
@@ -84,7 +84,7 @@
   std::vector<std::string> strs;
   for (const CoalescedPermissionMessage& msg : msgs)
     strs.push_back(PermissionIDsToString(msg.permissions()));
-  return base::JoinString(strs, " ");
+  return JoinString(strs, " ");
 }
 
 // Check that the given |permissions| produce a single warning message,