Avoid creating a layer for linear stretch

Bug: 187718492
Test: manual logging no layer updates during benchmark
Change-Id: I9a231625142e404882be6c53fa6d01b2fb81af1a

libs/hwui/RenderProperties.h

@@ -553,7 +553,7 @@ public:
     bool promotedToLayer() const {
         return mLayerProperties.mType == LayerType::None && fitsOnLayer() &&
                (mComputedFields.mNeedLayerForFunctors || mLayerProperties.mImageFilter != nullptr ||
-                !mLayerProperties.getStretchEffect().isEmpty() ||
+                mLayerProperties.getStretchEffect().requiresLayer() ||
                 (!MathUtils::isZero(mPrimitiveFields.mAlpha) && mPrimitiveFields.mAlpha < 1 &&
                  mPrimitiveFields.mHasOverlappingRendering));
     }

libs/hwui/effects/StretchEffect.h

@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include "Properties.h"
 #include "utils/MathUtils.h"
 
 #include <SkImage.h>
@@ -108,6 +109,11 @@ public:
         return matrix;
     }
 
+    bool requiresLayer() const {
+        return !(isEmpty() ||
+                 Properties::stretchEffectBehavior == StretchEffectBehavior::LinearScale);
+    }
+
 private:
     static sk_sp<SkRuntimeEffect> getStretchEffect();
     mutable SkVector mStretchDirection{0, 0};

libs/hwui/pipeline/skia/RenderNodeDrawable.cpp

@@ -171,16 +171,11 @@ void RenderNodeDrawable::forceDraw(SkCanvas* canvas) const {
     displayList->mProjectedOutline = nullptr;
 }
 
-static bool stretchNeedsLayer(const LayerProperties& properties) {
-    return Properties::stretchEffectBehavior != StretchEffectBehavior::LinearScale &&
-           !properties.getStretchEffect().isEmpty();
-}
-
 static bool layerNeedsPaint(const sk_sp<SkImage>& snapshotImage, const LayerProperties& properties,
                             float alphaMultiplier, SkPaint* paint) {
     if (alphaMultiplier < 1.0f || properties.alpha() < 255 ||
         properties.xferMode() != SkBlendMode::kSrcOver || properties.getColorFilter() != nullptr ||
-        properties.getImageFilter() != nullptr || stretchNeedsLayer(properties)) {
+        properties.getImageFilter() != nullptr || properties.getStretchEffect().requiresLayer()) {
         paint->setAlpha(properties.alpha() * alphaMultiplier);
         paint->setBlendMode(properties.xferMode());
         paint->setColorFilter(sk_ref_sp(properties.getColorFilter()));