Update layer hoisting code to correctly render sub-picture layers

src/gpu/GrPictureUtils.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPictureUtils_DEFINED
 #define GrPictureUtils_DEFINED
 
 #include "SkPicture.h"
-#include "SkTDArray.h"
+#include "SkTArray.h"
 
 // This class encapsulates the GPU-backend-specific acceleration data
 // for a single SkPicture
 class GrAccelData : public SkPicture::AccelData {
 public:
     // Information about a given saveLayer in an SkPicture
-    struct SaveLayerInfo {
-        // True if the SaveLayerInfo is valid. False if either 'fOffset' is
-        // invalid (due to a non-invertible CTM) or 'fPaint' is NULL (due
-        // to a non-copyable paint).
+    class SaveLayerInfo {
+    public:
+        SaveLayerInfo() : fPicture(NULL), fPaint(NULL) {}
+        ~SaveLayerInfo() { SkSafeUnref(fPicture); SkDELETE(fPaint); }
+
+        // True if the SaveLayerInfo is valid. False if 'fOffset' is
+        // invalid (due to a non-invertible CTM).
+        // TODO: remove fValid
         bool fValid;
-        // ID of the picture containing the layer. This can be the ID of
-        // a sub-picture embedded within the picture owning the GrAccelData
-        uint32_t fPictureID;
+        // The picture owning the layer. If the owning picture is the top-most
+        // one (i.e., the picture for which this GrAccelData was created) then
+        // this pointer is NULL. If it is a nested picture then the pointer
+        // is non-NULL and owns a ref on the picture.
+        const SkPicture* fPicture;
         // The size of the saveLayer
         SkISize fSize;
         // The matrix state in which this layer's draws must occur. It does not
         // include the translation needed to map the layer's top-left point to the origin.
         SkMatrix fOriginXform;
         // The offset that needs to be passed to drawBitmap to correctly
         // position the pre-rendered layer. It is in device space.
         SkIPoint fOffset;
-        // The paint to use on restore. NULL if the paint was not copyable (and
-        // thus that this layer should not be pulled forward).
+        // The paint to use on restore. Can be NULL since it is optional.
         const SkPaint* fPaint;
         // The ID of this saveLayer in the picture. 0 is an invalid ID.
         size_t  fSaveLayerOpID;
         // The ID of the matching restore in the picture. 0 is an invalid ID.
         size_t  fRestoreOpID;
         // True if this saveLayer has at least one other saveLayer nested within it.
         // False otherwise.
         bool    fHasNestedLayers;
         // True if this saveLayer is nested within another. False otherwise.
         bool    fIsNested;
     };
 
     GrAccelData(Key key) : INHERITED(key) { }
 
-    virtual ~GrAccelData() {
-        for (int i = 0; i < fSaveLayerInfo.count(); ++i) {
-            SkDELETE(fSaveLayerInfo[i].fPaint);
-        }
-    }
+    virtual ~GrAccelData() { }
 
-    void addSaveLayerInfo(const SaveLayerInfo& info) {
-        SkASSERT(info.fSaveLayerOpID < info.fRestoreOpID);
-        *fSaveLayerInfo.push() = info;
-    }
+    SaveLayerInfo& addSaveLayerInfo() { return fSaveLayerInfo.push_back(); }
 
     int numSaveLayers() const { return fSaveLayerInfo.count(); }
 
     const SaveLayerInfo& saveLayerInfo(int index) const {
         SkASSERT(index < fSaveLayerInfo.count());
 
         return fSaveLayerInfo[index];
     }
 
     // We may, in the future, need to pass in the GPUDevice in order to
     // incorporate the clip and matrix state into the key
     static SkPicture::AccelData::Key ComputeAccelDataKey();
 
 private:
-    SkTDArray<SaveLayerInfo> fSaveLayerInfo;
+    SkTArray<SaveLayerInfo, true> fSaveLayerInfo;
 
     typedef SkPicture::AccelData INHERITED;
 };
 
 const GrAccelData* GPUOptimize(const SkPicture* pict);
 
 #endif // GrPictureUtils_DEFINED