Make SkSmallAllocator obey the RAII invariants and be expandable

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 478 matching lines @@
                 // Make rawBounds include all paint outsets except for those due to image filters.
                 rawBounds = &apply_paint_to_bounds_sans_imagefilter(*fPaint, *rawBounds, &storage);
             }
             (void)canvas->internalSaveLayer(SkCanvas::SaveLayerRec(rawBounds, &tmp),
                                             SkCanvas::kFullLayer_SaveLayerStrategy);
             fTempLayerForImageFilter = true;
             // we remove the imagefilter/xfermode inside doNext()
         }
 
         if (SkDrawLooper* looper = paint.getLooper()) {
-            void* buffer = fLooperContextAllocator.reserveT<SkDrawLooper::Context>(
-                    looper->contextSize());
-            fLooperContext = looper->createContext(canvas, buffer);
+            fLooperContext = fLooperContextAllocator.createWithIniter(
+                looper->contextSize(),
+                [&](void* buffer) {
+                    return looper->createContext(canvas, buffer);
+                });
             fIsSimple = false;
         } else {
             fLooperContext = nullptr;
             // can we be marked as simple?
             fIsSimple = !fFilter && !fTempLayerForImageFilter;
         }
     }
 
     ~AutoDrawLooper() {
         if (fTempLayerForImageFilter) {
@@ skipping 2859 matching lines @@
 const SkCanvas::ClipOp SkCanvas::kXOR_Op;
 const SkCanvas::ClipOp SkCanvas::kReverseDifference_Op;
 const SkCanvas::ClipOp SkCanvas::kReplace_Op;
 
 static_assert((int)SkRegion::kDifference_Op         == (int)kDifference_SkClipOp, "");
 static_assert((int)SkRegion::kIntersect_Op          == (int)kIntersect_SkClipOp, "");
 static_assert((int)SkRegion::kUnion_Op              == (int)kUnion_SkClipOp, "");
 static_assert((int)SkRegion::kXOR_Op                == (int)kXOR_SkClipOp, "");
 static_assert((int)SkRegion::kReverseDifference_Op  == (int)kReverseDifference_SkClipOp, "");
 static_assert((int)SkRegion::kReplace_Op            == (int)kReplace_SkClipOp, "");