Add auto purging for SkPicture-related Ganesh resources (esp. layers)

include/core/SkPicture.h

 
 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPicture_DEFINED
@@ skipping 172 matching lines @@
     static bool InternalOnly_StreamIsSKP(SkStream*, SkPictInfo*);
     static bool InternalOnly_BufferIsSKP(SkReadBuffer&, SkPictInfo*);
 
     /** Return true if the picture is suitable for rendering on the GPU.
      */
 
 #if SK_SUPPORT_GPU
     bool suitableForGpuRasterization(GrContext*, const char ** = NULL) const;
 #endif
 
+    class DeletionListener : public SkRefCnt {
+    public:
+        virtual void onDeletion(uint32_t pictureID) = 0;
+    };
+
+    // Takes ref on listener.
+    void addDeletionListener(DeletionListener* listener) const;
+
 private:
     // V2 : adds SkPixelRef's generation ID.
     // V3 : PictInfo tag at beginning, and EOF tag at the end
     // V4 : move SkPictInfo to be the header
     // V5 : don't read/write FunctionPtr on cross-process (we can detect that)
     // V6 : added serialization of SkPath's bounds (and packed its flags tighter)
     // V7 : changed drawBitmapRect(IRect) to drawBitmapRectToRect(Rect)
     // V8 : Add an option for encoding bitmaps
     // V9 : Allow the reader and writer of an SKP disagree on whether to support
     //      SK_SUPPORT_HINTING_SCALE_FACTOR
@@ skipping 27 matching lines @@
     static const uint32_t MIN_PICTURE_VERSION = 19;
     static const uint32_t CURRENT_PICTURE_VERSION = 30;
 
     mutable uint32_t      fUniqueID;
 
     // TODO: make SkPictureData const when clone method goes away
     SkAutoTDelete<SkPictureData> fData;
     int                   fWidth, fHeight;
     mutable SkAutoTUnref<const AccelData> fAccelData;
 
+    mutable SkTDArray<DeletionListener*> fDeletionListeners;  // pointers are refed
+
     void needsNewGenID() { fUniqueID = SK_InvalidGenID; }
+    void callDeletionListeners();
 
     // Create a new SkPicture from an existing SkPictureData. The new picture
     // takes ownership of 'data'.
     SkPicture(SkPictureData* data, int width, int height);
 
     SkPicture(int width, int height, const SkPictureRecord& record, bool deepCopyOps);
 
     // An OperationList encapsulates a set of operation offsets into the picture byte
     // stream along with the CTMs needed for those operation.
     class OperationList : ::SkNoncopyable {
@@ skipping 25 matching lines @@
     friend class SkPictureReplacementPlayback; // to access OperationList
 
     typedef SkRefCnt INHERITED;
 
     SkPicture(int width, int height, SkRecord*);  // Takes ownership.
     SkAutoTDelete<SkRecord> fRecord;
     bool fRecordWillPlayBackBitmaps; // TODO: const
 };
 
 #endif