Infer NodeType in attachDiscardableAdapter.

This makes the call sites a bit simpler, doesn't materially change
anything in an optimized build, allows NRVO, and generally fixes a
number of warnings in gcc 9 about pessimizing-move.

Change-Id: I0ea5f57db163425da728630bfa6c1add7c416bd7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/278178
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Ben Wagner <bungeman@google.com>

modules/skottie/src/Path.cpp

@@ -42,7 +42,7 @@ private:
 } // namespace
 
 sk_sp<sksg::Path> AnimationBuilder::attachPath(const skjson::Value& jpath) const {
-    return this->attachDiscardableAdapter<PathAdapter, sk_sp<sksg::Path>>(jpath, *this);
+    return this->attachDiscardableAdapter<PathAdapter>(jpath, *this);
 }
 
 } // namespace internal

modules/skottie/src/SkottiePriv.h

@@ -118,16 +118,19 @@ public:
         }
     }
 
-    template <typename T,  typename NodeType = sk_sp<sksg::RenderNode>, typename... Args>
-    NodeType attachDiscardableAdapter(Args&&... args) const {
+    template <typename T, typename... Args>
+    auto attachDiscardableAdapter(Args&&... args) const ->
+        typename std::decay<decltype(T::Make(std::forward<Args>(args)...)->node())>::type
+    {
+        using NodeType =
+        typename std::decay<decltype(T::Make(std::forward<Args>(args)...)->node())>::type;
+
+        NodeType node;
         if (auto adapter = T::Make(std::forward<Args>(args)...)) {
-            auto node = adapter->node();
+            node = adapter->node();
             this->attachDiscardableAdapter(std::move(adapter));
-
-            return std::move(node);
         }
-
-        return nullptr;
+        return node;
     }
 
     class AutoPropertyTracker {

modules/skottie/src/layers/shapelayer/Ellipse.cpp

@@ -48,8 +48,7 @@ private:
 
 sk_sp<sksg::GeometryNode> ShapeBuilder::AttachEllipseGeometry(const skjson::ObjectValue& jellipse,
                                                               const AnimationBuilder* abuilder) {
-    return abuilder->attachDiscardableAdapter<EllipseGeometryAdapter, sk_sp<sksg::GeometryNode>>
-                (jellipse, abuilder);
+    return abuilder->attachDiscardableAdapter<EllipseGeometryAdapter>(jellipse, abuilder);
 }
 
 } // namespace internal

modules/skottie/src/layers/shapelayer/FillStroke.cpp

@@ -129,7 +129,7 @@ sk_sp<sksg::PaintNode> ShapeBuilder::AttachFill(const skjson::ObjectValue& jpain
                                                 const AnimationBuilder* abuilder,
                                                 sk_sp<sksg::PaintNode> paint_node,
                                                 sk_sp<AnimatablePropertyContainer> gradient) {
-    return abuilder->attachDiscardableAdapter<FillStrokeAdapter, sk_sp<sksg::PaintNode>>
+    return abuilder->attachDiscardableAdapter<FillStrokeAdapter>
             (jpaint,
              *abuilder,
              std::move(paint_node),
@@ -141,7 +141,7 @@ sk_sp<sksg::PaintNode> ShapeBuilder::AttachStroke(const skjson::ObjectValue& jpa
                                                   const AnimationBuilder* abuilder,
                                                   sk_sp<sksg::PaintNode> paint_node,
                                                   sk_sp<AnimatablePropertyContainer> gradient) {
-    return abuilder->attachDiscardableAdapter<FillStrokeAdapter, sk_sp<sksg::PaintNode>>
+    return abuilder->attachDiscardableAdapter<FillStrokeAdapter>
             (jpaint,
              *abuilder,
              std::move(paint_node),
@@ -173,7 +173,7 @@ std::vector<sk_sp<sksg::GeometryNode>> ShapeBuilder::AdjustStrokeGeometry(
     const skjson::ArrayValue* jdash = jstroke["d"];
     if (jdash && jdash->size() > 1) {
         for (size_t i = 0; i < geos.size(); ++i) {
-            geos[i] = abuilder->attachDiscardableAdapter<DashAdapter, sk_sp<sksg::GeometryNode>>(
+            geos[i] = abuilder->attachDiscardableAdapter<DashAdapter>(
                           *jdash, *abuilder, std::move(geos[i]));
         }
     }

modules/skottie/src/layers/shapelayer/Polystar.cpp

@@ -93,7 +93,7 @@ sk_sp<sksg::GeometryNode> ShapeBuilder::AttachPolystarGeometry(const skjson::Obj
         return nullptr;
     }
 
-    return abuilder->attachDiscardableAdapter<PolystarGeometryAdapter, sk_sp<sksg::GeometryNode>>
+    return abuilder->attachDiscardableAdapter<PolystarGeometryAdapter>
                 (jstar, abuilder, gTypes[type]);
 }
 

modules/skottie/src/layers/shapelayer/Rectangle.cpp

@@ -50,8 +50,7 @@ private:
 
 sk_sp<sksg::GeometryNode> ShapeBuilder::AttachRRectGeometry(const skjson::ObjectValue& jrect,
                                                             const AnimationBuilder* abuilder) {
-    return abuilder->attachDiscardableAdapter<RectangleGeometryAdapter, sk_sp<sksg::GeometryNode>>
-                (jrect, abuilder);
+    return abuilder->attachDiscardableAdapter<RectangleGeometryAdapter>(jrect, abuilder);
 }
 
 } // namespace internal

modules/skottie/src/layers/shapelayer/RoundCorners.cpp

@@ -47,7 +47,7 @@ std::vector<sk_sp<sksg::GeometryNode>> ShapeBuilder::AttachRoundGeometryEffect(
 
     for (auto& g : geos) {
         rounded.push_back(
-            abuilder->attachDiscardableAdapter<RoundCornersAdapter, sk_sp<sksg::RoundEffect>>
+            abuilder->attachDiscardableAdapter<RoundCornersAdapter>
                         (jround, *abuilder, std::move(g)));
     }
 

modules/skottie/src/layers/shapelayer/TrimPaths.cpp

@@ -95,8 +95,7 @@ std::vector<sk_sp<sksg::GeometryNode>> ShapeBuilder::AttachTrimGeometryEffect(
 
     for (const auto& i : inputs) {
         trimmed.push_back(
-            abuilder->attachDiscardableAdapter<TrimEffectAdapter, sk_sp<sksg::TrimEffect>>
-                        (jtrim, *abuilder, i));
+            abuilder->attachDiscardableAdapter<TrimEffectAdapter>(jtrim, *abuilder, i));
     }
 
     return trimmed;