Re-write many calls to WrapUnique() with MakeUnique()

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
index 86a76e25c8ed3f35079a4c580c73489dbca8cff0..4846718d486d1b6a2dc8b65f3596ec93f8a96f38 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
@@ -783,9 +783,9 @@ void MetricsWebContentsObserver::WillStartNavigationRequest(
   // committed_load_ or navigation_handle beyond the scope of the constructor.
   provisional_loads_.insert(std::make_pair(
       navigation_handle,
-      base::WrapUnique(new PageLoadTracker(
+      base::MakeUnique<PageLoadTracker>(
           in_foreground_, embedder_interface_.get(), currently_committed_url,
-          navigation_handle, chain_size, chain_size_same_url))));
+          navigation_handle, chain_size, chain_size_same_url)));
 }
 
 void MetricsWebContentsObserver::OnRequestComplete(