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/hardware_android.cc b/hardware_android.cc
index 1793e48..c388b82 100644
--- a/hardware_android.cc
+++ b/hardware_android.cc
@@ -21,11 +21,11 @@
 #include <sys/types.h>
 
 #include <algorithm>
+#include <memory>
 
 #include <bootloader.h>
 
 #include <base/files/file_util.h>
-#include <base/memory/ptr_util.h>
 #include <base/strings/stringprintf.h>
 #include <cutils/properties.h>
 
@@ -95,7 +95,7 @@
 
 // Factory defined in hardware.h.
 std::unique_ptr<HardwareInterface> CreateHardware() {
-  return base::MakeUnique<HardwareAndroid>();
+  return std::make_unique<HardwareAndroid>();
 }
 
 }  // namespace hardware