Make BBH parameter to SkRecordComputeLayers and SkRecordFillBounds optional

src/core/SkRecordDraw.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLayerInfo.h"
 #include "SkRecordDraw.h"
 #include "SkPatchUtils.h"
@@ skipping 150 matching lines @@
         while (!fSaveStack.isEmpty()) {
             this->popSaveBlock();
         }
 
         // Any control ops not part of any Save/Restore block draw everywhere.
         while (!fControlIndices.isEmpty()) {
             this->popControl(fCullRect);
         }
 
         // Finally feed all stored bounds into the BBH.  They'll be returned in this order.
-        SkASSERT(bbh);
-        bbh->insert(&fBounds, fNumRecords);
+        if (bbh) {
+            bbh->insert(&fBounds, fNumRecords);
+        }
     }
 
     template <typename T> void operator()(const T& op) {
         this->updateCTM(op);
         this->updateClipBounds(op);
         this->trackBounds(op);
     }
 
     // In this file, SkRect are in local coordinates, Bounds are translated back to identity space.
     typedef SkRect Bounds;
@@ skipping 561 matching lines @@
     SkRecords::CollectLayers visitor(cullRect, record, data);
 
     for (unsigned curOp = 0; curOp < record.count(); curOp++) {
         visitor.setCurrentOp(curOp);
         record.visit<void>(curOp, visitor);
     }
 
     visitor.cleanUp(bbh);
 }