ui/gfx: use SkLayerDrawLooper::Builder::addLayerOnTop instead of addLayer

ui/gfx/skia_util.cc

Index: ui/gfx/skia_util.cc
diff --git a/ui/gfx/skia_util.cc b/ui/gfx/skia_util.cc
index ef07241ba5778efd278d269f626852544574890f..90602f50f228aaaf533d0fa4e6a5a1be26825c85 100644
--- a/ui/gfx/skia_util.cc
+++ b/ui/gfx/skia_util.cc
@@ -4,6 +4,7 @@
 
 #include "ui/gfx/skia_util.h"
 
+#include "base/containers/adapters.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkColorPriv.h"
@@ -126,16 +127,12 @@ skia::RefPtr<SkDrawLooper> CreateShadowDrawLooper(
 
   SkLayerDrawLooper::Builder looper_builder;
 
-  looper_builder.addLayer();  // top layer of the original.
-
   SkLayerDrawLooper::LayerInfo layer_info;
   layer_info.fPaintBits |= SkLayerDrawLooper::kMaskFilter_Bit;
   layer_info.fPaintBits |= SkLayerDrawLooper::kColorFilter_Bit;
   layer_info.fColorMode = SkXfermode::kSrc_Mode;
 
-  for (size_t i = 0; i < shadows.size(); ++i) {
-    const ShadowValue& shadow = shadows[i];
-
+  for (const ShadowValue& shadow : base::Reversed(shadows)) {
     layer_info.fOffset.set(SkIntToScalar(shadow.x()),
                            SkIntToScalar(shadow.y()));
 
@@ -149,11 +146,14 @@ skia::RefPtr<SkDrawLooper> CreateShadowDrawLooper(
         SkColorFilter::CreateModeFilter(shadow.color(),
                                         SkXfermode::kSrcIn_Mode));
 
-    SkPaint* paint = looper_builder.addLayer(layer_info);
+    SkPaint* paint = looper_builder.addLayerOnTop(layer_info);
     paint->setMaskFilter(blur_mask.get());
     paint->setColorFilter(color_filter.get());
   }
 
+  // Top layer of the original.
+  looper_builder.addLayerOnTop(SkLayerDrawLooper::LayerInfo());
+
   return skia::AdoptRef<SkDrawLooper>(looper_builder.detachLooper());
 }