Remove superfluous error messages from nanobench

tools/SkBitmapRegionDecoderInterface.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapRegionCanvas.h"
 #include "SkBitmapRegionDecoderInterface.h"
 #include "SkBitmapRegionSampler.h"
 #include "SkCodec.h"
 #include "SkImageDecoder.h"
 
 SkBitmapRegionDecoderInterface* SkBitmapRegionDecoderInterface::CreateBitmapRegionDecoder(
         SkStreamRewindable* stream, Strategy strategy) {
     switch (strategy) {
         case kOriginal_Strategy: {
             SkImageDecoder* decoder = SkImageDecoder::Factory(stream);
             int width, height;
             if (nullptr == decoder) {
-                SkDebugf("Error: Could not create image decoder.\n");
                 return nullptr;
             }
             if (!decoder->buildTileIndex(stream, &width, &height)) {
-                SkDebugf("Error: Could not build tile index.\n");
                 delete decoder;
                 return nullptr;
             }
             return new SkBitmapRegionSampler(decoder, width, height);
         }
         case kCanvas_Strategy: {
             SkCodec* decoder = SkCodec::NewFromStream(stream);
             if (nullptr == decoder) {
-                SkDebugf("Error: Failed to create decoder.\n");
                 return nullptr;
             }
             switch (decoder->getScanlineOrder()) {
                 case SkCodec::kTopDown_SkScanlineOrder:
                 case SkCodec::kNone_SkScanlineOrder:
                     break;
                 default:
-                    SkDebugf("Error: Scanline ordering not supported.\n");
                     return nullptr;
             }
             return new SkBitmapRegionCanvas(decoder);
         }
         default:
             SkASSERT(false);
             return nullptr;
     }
 }