make LayerIter private, and remove skipClip option

src/utils/SkCanvasStateUtils.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvasStateUtils.h"
 
 #include "SkCanvas.h"
@@ skipping 204 matching lines @@
 
     /*
      * decompose the layers
      *
      * storage is allocated on the stack for the first 3 layers. It is common in
      * some view systems (e.g. Android) that a few non-clipped layers are present
      * and we will not need to malloc any additional memory in those cases.
      */
     SkSWriter32<3*sizeof(SkCanvasLayerState)> layerWriter;
     int layerCount = 0;
-    for (SkCanvas::LayerIter layer(canvas, true/*skipEmptyClips*/); !layer.done(); layer.next()) {
+    for (SkCanvas::LayerIter layer(canvas); !layer.done(); layer.next()) {
 
         // we currently only work for bitmap backed devices
         SkPixmap pmap;
         if (!layer.device()->accessPixels(&pmap) || 0 == pmap.width() || 0 == pmap.height()) {
             return nullptr;
         }
 
         SkCanvasLayerState* layerState =
                 (SkCanvasLayerState*) layerWriter.reserve(sizeof(SkCanvasLayerState));
         layerState->type = kRaster_CanvasBackend;
@@ skipping 110 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 
 void SkCanvasStateUtils::ReleaseCanvasState(SkCanvasState* state) {
     SkASSERT(!state || SkCanvasState_v1::kVersion == state->version);
     // Upcast to the correct version of SkCanvasState. This avoids having a virtual destructor on
     // SkCanvasState. That would be strange since SkCanvasState has no other virtual functions, and
     // instead uses the field "version" to determine how to behave.
     delete static_cast<SkCanvasState_v1*>(state);
 }