Revert of [SVGDom] Opacity optimization (patchset #4 id:60001 of https://codereview.chromium.org/2353503005/ )

Reason for revert:
Failing assertion

Original issue's description:
> [SVGDom] Opacity optimization
>
> Apply opacity as fill/stroke paint alpha instead of saveLayer, when
> possible.
>
> R=robertphillips@google.com,stephana@google.com,reed@google.com
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2353503005
>
> Committed: https://skia.googlesource.com/skia/+/3dbb7b9f196d793fbd16243157ee67638891f5dc

TBR=reed@google.com,robertphillips@google.com,stephana@google.com,fmalita@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.chromium.org/2359603002

6 files changed, 6 insertions, 47 deletions

diff --git a/experimental/svg/model/SkSVGContainer.cpp b/experimental/svg/model/SkSVGContainer.cpp
index af19608d25..4f91b30bab 100644
--- a/experimental/svg/model/SkSVGContainer.cpp
+++ b/experimental/svg/model/SkSVGContainer.cpp
@@ -14,10 +14,6 @@ void SkSVGContainer::appendChild(sk_sp<SkSVGNode> node) {
     fChildren.push_back(std::move(node));
 }
 
-bool SkSVGContainer::hasChildren() const {
-    return !fChildren.empty();
-}
-
 void SkSVGContainer::onRender(const SkSVGRenderContext& ctx) const {
     for (int i = 0; i < fChildren.count(); ++i) {
         fChildren[i]->render(ctx);
diff --git a/experimental/svg/model/SkSVGContainer.h b/experimental/svg/model/SkSVGContainer.h
index 25296fcddb..73c7c1803b 100644
--- a/experimental/svg/model/SkSVGContainer.h
+++ b/experimental/svg/model/SkSVGContainer.h
@@ -22,8 +22,6 @@ protected:
 
     void onRender(const SkSVGRenderContext&) const override;
 
-    bool hasChildren() const final;
-
     // TODO: add some sort of child iterator, and hide the container.
     SkSTArray<1, sk_sp<SkSVGNode>, true> fChildren;
 
diff --git a/experimental/svg/model/SkSVGNode.cpp b/experimental/svg/model/SkSVGNode.cpp
index f40ee5dadb..012c7d2277 100644
--- a/experimental/svg/model/SkSVGNode.cpp
+++ b/experimental/svg/model/SkSVGNode.cpp
@@ -31,8 +31,7 @@ bool SkSVGNode::asPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
 }
 
 bool SkSVGNode::onPrepareToRender(SkSVGRenderContext* ctx) const {
-    ctx->applyPresentationAttributes(fPresentationAttributes,
-                                     this->hasChildren() ? 0 : SkSVGRenderContext::kLeaf);
+    ctx->applyPresentationAttributes(fPresentationAttributes);
     return true;
 }
 
diff --git a/experimental/svg/model/SkSVGNode.h b/experimental/svg/model/SkSVGNode.h
index 2a7c836413..dcdb58958a 100644
--- a/experimental/svg/model/SkSVGNode.h
+++ b/experimental/svg/model/SkSVGNode.h
@@ -69,8 +69,6 @@ protected:
 
     virtual void onSetAttribute(SkSVGAttribute, const SkSVGValue&);
 
-    virtual bool hasChildren() const { return false; }
-
 private:
     SkSVGTag                    fTag;
 
diff --git a/experimental/svg/model/SkSVGRenderContext.cpp b/experimental/svg/model/SkSVGRenderContext.cpp
index 147d64edb3..7e2e90e22c 100644
--- a/experimental/svg/model/SkSVGRenderContext.cpp
+++ b/experimental/svg/model/SkSVGRenderContext.cpp
@@ -239,8 +239,7 @@ const SkSVGNode* SkSVGRenderContext::findNodeById(const SkString& id) const {
     return v ? v->get() : nullptr;
 }
 
-void SkSVGRenderContext::applyPresentationAttributes(const SkSVGPresentationAttributes& attrs,
-                                                     uint32_t flags) {
+void SkSVGRenderContext::applyPresentationAttributes(const SkSVGPresentationAttributes& attrs) {
 
 #define ApplyLazyInheritedAttribute(ATTR)                                               \
     do {                                                                                \
@@ -268,36 +267,10 @@ void SkSVGRenderContext::applyPresentationAttributes(const SkSVGPresentationAttr
 
     // Uninherited attributes.  Only apply to the current context.
 
-    if (auto* opacity = attrs.fOpacity.getMaybeNull()) {
-        this->applyOpacity(opacity->value(), flags);
-    }
-}
-
-void SkSVGRenderContext::applyOpacity(SkScalar opacity, uint32_t flags) {
-    if (opacity >= 1) {
-        return;
-    }
-
-    const bool hasFill   = SkToBool(this->fillPaint());
-    const bool hasStroke = SkToBool(this->strokePaint());
-
-    // We can apply the opacity as paint alpha iif it only affects one atomic draw.
-    // For now, this means a) the target node doesn't have any descendants, and
-    // b) it only has a stroke or a fill (but not both).  Going forward, we may need
-    // to refine this heuristic (e.g. to accommodate markers).
-    if ((flags & kLeaf) && (hasFill ^ hasStroke)) {
-        auto* pctx = fPresentationContext.writable();
-        if (hasFill) {
-            pctx->fFillPaint.setAlpha(
-                SkScalarRoundToInt(opacity * pctx->fFillPaint.getAlpha()));
-        } else {
-            pctx->fStrokePaint.setAlpha(
-                SkScalarRoundToInt(opacity * pctx->fStrokePaint.getAlpha()));
-        }
-    } else {
-        // Expensive, layer-based fall back.
+    auto* opacity = attrs.fOpacity.getMaybeNull();
+    if (opacity && opacity->value() < 1) {
         SkPaint opacityPaint;
-        opacityPaint.setAlpha(opacity_to_alpha(opacity));
+        opacityPaint.setAlpha(opacity_to_alpha(opacity->value()));
         // Balanced in the destructor, via restoreToCount().
         fCanvas->saveLayer(nullptr, &opacityPaint);
     }
diff --git a/experimental/svg/model/SkSVGRenderContext.h b/experimental/svg/model/SkSVGRenderContext.h
index 393c2849eb..68209a73cc 100644
--- a/experimental/svg/model/SkSVGRenderContext.h
+++ b/experimental/svg/model/SkSVGRenderContext.h
@@ -67,10 +67,7 @@ public:
 
     SkCanvas* canvas() const { return fCanvas; }
 
-    enum ApplyFlags {
-        kLeaf = 1 << 0, // the target node doesn't have descendants
-    };
-    void applyPresentationAttributes(const SkSVGPresentationAttributes&, uint32_t flags);
+    void applyPresentationAttributes(const SkSVGPresentationAttributes&);
 
     const SkSVGNode* findNodeById(const SkString&) const;
 
@@ -83,8 +80,6 @@ private:
     void* operator new(size_t, void*)                        = delete;
     SkSVGRenderContext& operator=(const SkSVGRenderContext&) = delete;
 
-    void applyOpacity(SkScalar opacity, uint32_t flags);
-
     const SkSVGIDMapper&                          fIDMapper;
     SkTCopyOnFirstWrite<SkSVGLengthContext>       fLengthContext;
     SkTCopyOnFirstWrite<SkSVGPresentationContext> fPresentationContext;