update_engine: migrate from base::MakeUnique to std::make_unique

base::MakeUnique is being deprecated as we can now use std::make_unique
when compiling code in the C++14 mode.

BUG=chromium:769107
CQ-DEPEND=CL:669672
TEST=Run unit tests.

Change-Id: I82f76647239b1eb3b98b19f6479788ffd86ce756
Reviewed-on: https://chromium-review.googlesource.com/716826
Commit-Ready: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Sen Jiang <senj@chromium.org>
diff --git a/payload_generator/zip_unittest.cc b/payload_generator/zip_unittest.cc
index 308ba2f..c750eb7 100644
--- a/payload_generator/zip_unittest.cc
+++ b/payload_generator/zip_unittest.cc
@@ -17,10 +17,10 @@
 #include <string.h>
 #include <unistd.h>
 
+#include <memory>
 #include <string>
 #include <vector>
 
-#include <base/memory/ptr_util.h>
 #include <gtest/gtest.h>
 
 #include "update_engine/common/test_utils.h"
@@ -71,7 +71,7 @@
 template <typename W>
 bool DecompressWithWriter(const brillo::Blob& in, brillo::Blob* out) {
   std::unique_ptr<ExtentWriter> writer(
-      new W(base::MakeUnique<MemoryExtentWriter>(out)));
+      new W(std::make_unique<MemoryExtentWriter>(out)));
   // Init() parameters are ignored by the testing MemoryExtentWriter.
   bool ok = writer->Init(nullptr, {}, 1);
   ok = writer->Write(in.data(), in.size()) && ok;