Replace base string utils with android::base ones

Test: th
Change-Id: I62c1dfb24ec1dae3cdc5e0a0a93ea2b48e9967e5
diff --git a/payload_consumer/filesystem_verifier_action.cc b/payload_consumer/filesystem_verifier_action.cc
index 4990358..8c21673 100644
--- a/payload_consumer/filesystem_verifier_action.cc
+++ b/payload_consumer/filesystem_verifier_action.cc
@@ -31,7 +31,6 @@
 #include <utility>
 
 #include <base/bind.h>
-#include <base/strings/string_util.h>
 #include <brillo/data_encoding.h>
 #include <brillo/message_loops/message_loop.h>
 #include <brillo/secure_blob.h>
@@ -357,8 +356,8 @@
   if (partition_index_ == install_plan_.partitions.size()) {
     if (!install_plan_.untouched_dynamic_partitions.empty()) {
       LOG(INFO) << "Verifying extents of untouched dynamic partitions ["
-                << base::JoinString(install_plan_.untouched_dynamic_partitions,
-                                    ", ")
+                << android::base::Join(
+                       install_plan_.untouched_dynamic_partitions, ", ")
                 << "]";
       if (!dynamic_control_->VerifyExtentsForUntouchedPartitions(
               install_plan_.source_slot,