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/omaha_request_action_unittest.cc b/omaha_request_action_unittest.cc
index c7ef0c7..b1cf31c 100644
--- a/omaha_request_action_unittest.cc
+++ b/omaha_request_action_unittest.cc
@@ -18,6 +18,7 @@
 
 #include <stdint.h>
 
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -1103,7 +1104,7 @@
   OmahaRequestAction action(
       &fake_system_state_,
       nullptr,
-      base::MakeUnique<MockHttpFetcher>(http_response.data(),
+      std::make_unique<MockHttpFetcher>(http_response.data(),
                                         http_response.size(),
                                         nullptr),
       false);
@@ -1276,7 +1277,7 @@
   OmahaRequestAction action(
       &fake_system_state_,
       nullptr,
-      base::MakeUnique<MockHttpFetcher>(http_response.data(),
+      std::make_unique<MockHttpFetcher>(http_response.data(),
                                         http_response.size(),
                                         nullptr),
       false);
@@ -1489,7 +1490,7 @@
   OmahaRequestAction update_check_action(
       &fake_system_state_,
       nullptr,
-      base::MakeUnique<MockHttpFetcher>(http_response.data(),
+      std::make_unique<MockHttpFetcher>(http_response.data(),
                                         http_response.size(),
                                         nullptr),
       false);
@@ -1500,7 +1501,7 @@
   OmahaRequestAction event_action(
       &fake_system_state_,
       new OmahaEvent(OmahaEvent::kTypeUpdateComplete),
-      base::MakeUnique<MockHttpFetcher>(http_response.data(),
+      std::make_unique<MockHttpFetcher>(http_response.data(),
                                         http_response.size(),
                                         nullptr),
       false);