Use std::unique_ptr to signal ownership transfer in WebCompositorSupport

cc/blink/web_scrollbar_layer_impl.cc

Index: cc/blink/web_scrollbar_layer_impl.cc
diff --git a/cc/blink/web_scrollbar_layer_impl.cc b/cc/blink/web_scrollbar_layer_impl.cc
index 7011d5fc91ef5f7f115f15b152b3feac2db34542..b9c6df38b6c1db6a7e1feb25c181e288e9a02a64 100644
--- a/cc/blink/web_scrollbar_layer_impl.cc
+++ b/cc/blink/web_scrollbar_layer_impl.cc
@@ -4,6 +4,8 @@
 
 #include "cc/blink/web_scrollbar_layer_impl.h"
 
+#include <utility>
+
 #include "base/memory/ptr_util.h"
 #include "cc/blink/scrollbar_impl.h"
 #include "cc/blink/web_layer_impl.h"
@@ -28,15 +30,13 @@ cc::ScrollbarOrientation ConvertOrientation(
 namespace cc_blink {
 
 WebScrollbarLayerImpl::WebScrollbarLayerImpl(
-    blink::WebScrollbar* scrollbar,
+    std::unique_ptr<blink::WebScrollbar> scrollbar,
     blink::WebScrollbarThemePainter painter,
-    blink::WebScrollbarThemeGeometry* geometry)
+    std::unique_ptr<blink::WebScrollbarThemeGeometry> geometry)
     : layer_(new WebLayerImpl(PaintedScrollbarLayer::Create(
-
-          std::unique_ptr<cc::Scrollbar>(
-              new ScrollbarImpl(base::WrapUnique(scrollbar),
-                                painter,
-                                base::WrapUnique(geometry))),
+          base::MakeUnique<ScrollbarImpl>(std::move(scrollbar),
+                                          painter,
+                                          std::move(geometry)),
           0))) {}
 
 WebScrollbarLayerImpl::WebScrollbarLayerImpl(