Use variable length key (rather than accumulated matrix) as save layer hoisting key

src/core/SkRecordDraw.cpp

Index: src/core/SkRecordDraw.cpp
diff --git a/src/core/SkRecordDraw.cpp b/src/core/SkRecordDraw.cpp
index 7e35d8a2c7da87867c84079fd19d72ef007c5cbb..a086197453d78e7a0c27b8c8a99a353f8f55deda 100644
--- a/src/core/SkRecordDraw.cpp
+++ b/src/core/SkRecordDraw.cpp
@@ -682,6 +682,11 @@ private:
             dst.fRestoreOpID = src.fRestoreOpID;
             dst.fHasNestedLayers = src.fHasNestedLayers;
             dst.fIsNested = fSaveLayersInStack > 0 || src.fIsNested;
+
+            dst.fKeySize = fSaveLayerOpStack.count() + src.fKeySize;
+            dst.fKey = SkNEW_ARRAY(int, dst.fKeySize);
+            memcpy(dst.fKey, fSaveLayerOpStack.begin(), fSaveLayerOpStack.count() * sizeof(int));
+            memcpy(&dst.fKey[fSaveLayerOpStack.count()], src.fKey, src.fKeySize * sizeof(int));
         }
     }
 
@@ -737,12 +742,17 @@ private:
         block.fRestoreOpID = fFillBounds.currentOp();
         block.fHasNestedLayers = sli.fHasNestedSaveLayer;
         block.fIsNested = fSaveLayersInStack > 0;
+
+        block.fKeySize = fSaveLayerOpStack.count();
+        block.fKey = SkNEW_ARRAY(int, block.fKeySize);
+        memcpy(block.fKey, fSaveLayerOpStack.begin(), block.fKeySize * sizeof(int));
     }
 
     // Used to collect saveLayer information for layer hoisting
-    int                   fSaveLayersInStack;
+    int                      fSaveLayersInStack;
     SkTDArray<SaveLayerInfo> fSaveLayerStack;
-    SkLayerInfo*          fAccelData;
+    SkTDArray<int>           fSaveLayerOpStack;
+    SkLayerInfo*             fAccelData;
 
     SkRecords::FillBounds fFillBounds;
 };