check for null-layer-paint after prev fix to savelayer ops

src/core/SkRecordOpts.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRecordOpts.h"
 
 #include "SkRecordPattern.h"
@@ skipping 69 matching lines @@
                     Is<Restore>>
         Match;
 
     bool onMatch(SkRecord* record, Match*, int begin, int end) {
         record->replace<NoOp>(begin);  // Save
         record->replace<NoOp>(end-1);  // Restore
         return true;
     }
 };
 
-static bool fold_opacity_layer_color_to_paint(const SkPaint& layerPaint,
+static bool fold_opacity_layer_color_to_paint(const SkPaint* layerPaint,
                                               bool isSaveLayer,
                                               SkPaint* paint) {
     // We assume layerPaint is always from a saveLayer.  If isSaveLayer is
     // true, we assume paint is too.
 
     // The alpha folding can proceed if the filter layer paint does not have properties which cause
     // the resulting filter layer to be "blended" in complex ways to the parent layer. For example,
     // looper drawing unmodulated filter layer twice and then modulating the result produces
     // different image to drawing modulated filter layer twice.
     // TODO: most likely the looper and only some xfer modes are the hard constraints
@@ skipping 13 matching lines @@
     if (paint->getColorFilter()) {
         // Filter input depends on the paint color.
 
         // Here we could filter the color if we knew the draw is going to be uniform color.  This
         // should be detectable as drawPath/drawRect/.. without a shader being uniform, while
         // drawBitmap/drawSprite or a shader being non-uniform. However, current matchers don't
         // give the type out easily, so just do not optimize that at the moment.
         return false;
     }
 
-    const uint32_t layerColor = layerPaint.getColor();
+    const uint32_t layerColor = layerPaint ? layerPaint->getColor() : SK_ColorBLACK;

[mtklein, 2016/09/06 16:00:53]

How about

if (layerPaint) {
  SkColor layerColor = layerPaint->getColor();
  // The layer paint color must have only alpha component.
  if (SK_ColorTRANSPARENT != SkColorSetA(layerColor, SK_AlphaTRANSPARENT)) {
    return false;
  }

  // The layer paint can not have any effects.
  if (layerPaint->getPathEffect() || ... ) {
    return false;
  }

  paint->setAlpha(SkMulDiv255Round(paint->getAlpha(), SkColorGetA(layerColor)));
}

return true;

[reed1, 2016/09/06 16:49:44]

Done.

     // The layer paint color must have only alpha component.
     if (SK_ColorTRANSPARENT != SkColorSetA(layerColor, SK_AlphaTRANSPARENT)) {
         return false;
     }
 
-    // The layer paint can not have any effects.
-    if (layerPaint.getPathEffect() ||
-        layerPaint.getShader()      ||
-        layerPaint.getXfermode()    ||
-        layerPaint.getMaskFilter()  ||
-        layerPaint.getColorFilter() ||
-        layerPaint.getRasterizer()  ||
-        layerPaint.getLooper()      ||
-        layerPaint.getImageFilter()) {
-        return false;
+    if (layerPaint) {
+        // The layer paint can not have any effects.
+        if (layerPaint->getPathEffect() ||
+            layerPaint->getShader()      ||
+            layerPaint->getXfermode()    ||
+            layerPaint->getMaskFilter()  ||
+            layerPaint->getColorFilter() ||
+            layerPaint->getRasterizer()  ||
+            layerPaint->getLooper()      ||
+            layerPaint->getImageFilter()) {
+            return false;
+        }
     }
 
     paint->setAlpha(SkMulDiv255Round(paint->getAlpha(), SkColorGetA(layerColor)));
 
     return true;
 }
 
 // Turns logical no-op Save-[non-drawing command]*-Restore patterns into actual no-ops.
 struct SaveNoDrawsRestoreNooper {
     // Greedy matches greedily, so we also have to exclude Save and Restore.
@@ skipping 54 matching lines @@
             // There wasn't really any point to this SaveLayer at all.
             return KillSaveLayerAndRestore(record, begin);
         }
 
         if (drawPaint == nullptr) {
             // We can just give the draw the SaveLayer's paint.
             // TODO(mtklein): figure out how to do this clearly
             return false;
         }
 
-        if (!fold_opacity_layer_color_to_paint(*layerPaint, false /*isSaveLayer*/, drawPaint)) {
+        if (!fold_opacity_layer_color_to_paint(layerPaint, false /*isSaveLayer*/, drawPaint)) {
             return false;
         }
 
         return KillSaveLayerAndRestore(record, begin);
     }
 
     static bool KillSaveLayerAndRestore(SkRecord* record, int saveLayerIndex) {
         record->replace<NoOp>(saveLayerIndex);    // SaveLayer
         record->replace<NoOp>(saveLayerIndex+2);  // Restore
         return true;
@@ skipping 32 matching lines @@
 
         // This layer typically contains a filter, but this should work for layers with for other
         // purposes too.
         SkPaint* filterLayerPaint = match->fourth<SaveLayer>()->paint;
         if (filterLayerPaint == nullptr) {
             // We can just give the inner SaveLayer the paint of the outer SaveLayer.
             // TODO(mtklein): figure out how to do this clearly
             return false;
         }
 
-        if (!fold_opacity_layer_color_to_paint(*opacityPaint, true /*isSaveLayer*/,
+        if (!fold_opacity_layer_color_to_paint(opacityPaint, true /*isSaveLayer*/,
                                                filterLayerPaint)) {
             return false;
         }
 
         return KillSaveLayerAndRestore(record, begin);
     }
 
     static bool KillSaveLayerAndRestore(SkRecord* record, int saveLayerIndex) {
         record->replace<NoOp>(saveLayerIndex);     // SaveLayer
         record->replace<NoOp>(saveLayerIndex + 6); // Restore
@@ skipping 25 matching lines @@
 }
 
 void SkRecordOptimize2(SkRecord* record) {
     multiple_set_matrices(record);
     SkRecordNoopSaveRestores(record);
     SkRecordNoopSaveLayerDrawRestores(record);
     SkRecordMergeSvgOpacityAndFilterLayers(record);
 
     record->defrag();
 }