remove fClipStack and attach/deattach-from-canvas

src/core/SkCanvas.cpp

 /*
  * Copyright 2008 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.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
 #include "SkCanvasPriv.h"
@@ skipping 189 matching lines @@
     const SkMatrix*     fMatrix;
     SkMatrix            fMatrixStorage;
     SkMatrix            fStashedMatrix; // original CTM; used by imagefilter in saveLayer
 
     DeviceCM(SkBaseDevice* device, const SkPaint* paint, SkCanvas* canvas,
              bool conservativeRasterClip, const SkMatrix& stashed)
         : fNext(nullptr)
         , fClip(conservativeRasterClip)
         , fStashedMatrix(stashed)
     {
-        if (nullptr != device) {
-            device->ref();
-            device->onAttachToCanvas(canvas);
-        }
+        SkSafeRef(device);
         fDevice = device;
         fPaint = paint ? new SkPaint(*paint) : nullptr;
     }
 
     ~DeviceCM() {
-        if (fDevice) {
-            fDevice->onDetachFromCanvas();
-            fDevice->unref();
-        }
+        SkSafeUnref(fDevice);
         delete fPaint;
     }
 
     void reset(const SkIRect& bounds) {
         SkASSERT(!fPaint);
         SkASSERT(!fNext);
         SkASSERT(fDevice);
         fClip.setRect(bounds);
     }
 
@@ skipping 444 matching lines @@
     new (fDeviceCMStorage) DeviceCM(nullptr, nullptr, nullptr, fConservativeRasterClip,
                                     fMCRec->fMatrix);
 
     fMCRec->fTopLayer = fMCRec->fLayer;
 
     fSurfaceBase = nullptr;
 
     if (device) {
         // The root device and the canvas should always have the same pixel geometry
         SkASSERT(fProps.pixelGeometry() == device->surfaceProps().pixelGeometry());
-        device->onAttachToCanvas(this);
         fMCRec->fLayer->fDevice = SkRef(device);
         fMCRec->fRasterClip.setRect(device->getGlobalBounds());
     }
     return device;
 }
 
 SkCanvas::SkCanvas()
     : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage))
     , fProps(SkSurfaceProps::kLegacyFontHost_InitType)
     , fConservativeRasterClip(false)
@@ skipping 2436 matching lines @@
 
 SkAutoCanvasMatrixPaint::~SkAutoCanvasMatrixPaint() {
     fCanvas->restoreToCount(fSaveCount);
 }
 
 #ifdef SK_SUPPORT_LEGACY_NEW_SURFACE_API
 SkSurface* SkCanvas::newSurface(const SkImageInfo& info, const SkSurfaceProps* props) {
     return this->makeSurface(info, props).release();
 }
 #endif