Fix build (warning).

tools/skimage_main.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
 #include "SkCommandLineFlags.h"
@@ skipping 188 matching lines @@
                 SkString subsetDim = SkStringPrintf("[%d,%d,%d,%d]", rect.fLeft, rect.fTop,
                                                     rect.fRight, rect.fBottom);
                 if (codec->decodeSubset(&bitmapFromDecodeSubset, rect, SkBitmap::kNo_Config)) {
                     gSuccessfulSubsetDecodes.push_back().printf("Decoded subset %s from %s",
                                                           subsetDim.c_str(), srcPath);
                     if (writePath != NULL) {
                         // Write the region to a file whose name includes the dimensions.
                         SkString suffix = SkStringPrintf("_%s.png", subsetDim.c_str());
                         SkString outPath;
                         make_outname(&outPath, writePath->c_str(), srcPath, suffix.c_str());
-                        bool success = write_bitmap(outPath.c_str(), &bitmapFromDecodeSubset);
+                        SkDEBUGCODE(bool success =)
+                        write_bitmap(outPath.c_str(), &bitmapFromDecodeSubset);
                         SkASSERT(success);
                         gSuccessfulSubsetDecodes.push_back().printf("\twrote %s", outPath.c_str());
                         // Also use extractSubset from the original for visual comparison.
                         SkBitmap extractedSubset;
                         if (bitmap.extractSubset(&extractedSubset, rect)) {
                             suffix.printf("_%s_extracted.png", subsetDim.c_str());
                             make_outname(&outPath, writePath->c_str(), srcPath, suffix.c_str());
                             success = write_bitmap(outPath.c_str(), &extractedSubset);
                             SkASSERT(success);
                         }
@@ skipping 163 matching lines @@
     }
 
     return failed ? -1 : 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif