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

src/core/SkRecordDraw.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 "SkLayerInfo.h"
 #include "SkRecordDraw.h"
 #include "SkPatchUtils.h"
@@ skipping 674 matching lines @@
             dst.fLocalMat = src.fLocalMat;
             dst.fPreMat = src.fPreMat;
             dst.fPreMat.postConcat(fFillBounds.ctm());
             if (src.fPaint) {
                 dst.fPaint = SkNEW_ARGS(SkPaint, (*src.fPaint));
             }
             dst.fSaveLayerOpID = src.fSaveLayerOpID;
             dst.fRestoreOpID = src.fRestoreOpID;
             dst.fHasNestedLayers = src.fHasNestedLayers;
             dst.fIsNested = fSaveLayersInStack > 0 || src.fIsNested;
+
+            // Store 'saveLayer ops from enclosing picture' + drawPict op + 'ops from sub-picture'
+            dst.fKeySize = fSaveLayerOpStack.count() + src.fKeySize + 1;
+            dst.fKey = SkNEW_ARRAY(int, dst.fKeySize);
+            memcpy(dst.fKey, fSaveLayerOpStack.begin(), fSaveLayerOpStack.count() * sizeof(int));
+            dst.fKey[fSaveLayerOpStack.count()] = fFillBounds.currentOp();
+            memcpy(&dst.fKey[fSaveLayerOpStack.count()+1], src.fKey, src.fKeySize * sizeof(int));
         }
     }
 
     void trackSaveLayers(const DrawPicture& dp) {
         this->trackSaveLayersForPicture(dp.picture, dp.paint);
     }
 
     void trackSaveLayers(const DrawDrawable& dp) {
         SkASSERT(fPictList);
         SkASSERT(dp.index >= 0 && dp.index < fPictList->count());
@@ skipping 12 matching lines @@
             if (fSaveLayerStack[index].fIsSaveLayer) {
                 break;
             }
         }
     }
 
     void pushSaveLayerInfo(bool isSaveLayer, const SkPaint* paint) {
         if (isSaveLayer) {
             this->updateStackForSaveLayer();
             ++fSaveLayersInStack;
+            fSaveLayerOpStack.push(fFillBounds.currentOp());
         }
 
         fSaveLayerStack.push(SaveLayerInfo(fFillBounds.currentOp(), isSaveLayer, paint));
     }
 
     void popSaveLayerInfo() {
         if (fSaveLayerStack.count() <= 0) {
             SkASSERT(false);
             return;
         }
 
+        SkASSERT(fSaveLayersInStack == fSaveLayerOpStack.count());
+
         SaveLayerInfo sli;
         fSaveLayerStack.pop(&sli);
 
         if (!sli.fIsSaveLayer) {
             return;
         }
 
         --fSaveLayersInStack;
 
         SkLayerInfo::BlockInfo& block = fAccelData->addBlock();
 
         SkASSERT(NULL == block.fPicture);  // This layer is in the top-most picture
 
         block.fBounds = fFillBounds.getBounds(sli.fStartIndex);
         block.fLocalMat = fFillBounds.ctm();
         block.fPreMat = SkMatrix::I();
         if (sli.fPaint) {
             block.fPaint = SkNEW_ARGS(SkPaint, (*sli.fPaint));
         }
         block.fSaveLayerOpID = sli.fStartIndex;
         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));
+
+        fSaveLayerOpStack.pop();
     }
 
     // Used to collect saveLayer information for layer hoisting
-    int                   fSaveLayersInStack;
+    int                      fSaveLayersInStack;
     SkTDArray<SaveLayerInfo> fSaveLayerStack;
-    SkLayerInfo*          fAccelData;
+    // The op code indices of all the currently active saveLayers
+    SkTDArray<int>           fSaveLayerOpStack;
+    SkLayerInfo*             fAccelData;
     const SkPicture::SnapshotArray* fPictList;
 
     SkRecords::FillBounds fFillBounds;
 };
 
 }  // namespace SkRecords
 
 void SkRecordFillBounds(const SkRect& cullRect, const SkRecord& record, SkBBoxHierarchy* bbh) {
     SkRecords::FillBounds visitor(cullRect, record);
 
@@ skipping 11 matching lines @@
     SkRecords::CollectLayers visitor(cullRect, record, pictList, data);
 
     for (unsigned curOp = 0; curOp < record.count(); curOp++) {
         visitor.setCurrentOp(curOp);
         record.visit<void>(curOp, visitor);
     }
 
     visitor.cleanUp(bbh);
 }