Fix assert in skimage test.

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 "gm_expectations.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 569 matching lines @@
 
     write_expectations(bitmapAndDigest, filename);
 
     if (FLAGS_testSubsetDecoding) {
         SkDEBUGCODE(bool couldRewind =) stream.rewind();
         SkASSERT(couldRewind);
         int width, height;
         // Build the tile index for decoding subsets. If the image is 1x1, skip subset
         // decoding since there are no smaller subsets.
         if (codec->buildTileIndex(&stream, &width, &height) && width > 1 && height > 1) {
-            SkASSERT(bitmap.width() == width && bitmap.height() == height);
+            SkASSERT((bitmap.width() == width && bitmap.height() == height)
+                     || FLAGS_sampleSize != 1);
             // Call decodeSubset multiple times:
             SkRandom rand(0);
             for (int i = 0; i < 5; i++) {
                 SkBitmap bitmapFromDecodeSubset;
                 // FIXME: Come up with a more representative set of rectangles.
                 SkIRect rect = generate_random_rect(&rand, width, height);
                 SkString subsetDim = SkStringPrintf("%d_%d_%d_%d", rect.fLeft, rect.fTop,
                                                     rect.fRight, rect.fBottom);
                 if (codec->decodeSubset(&bitmapFromDecodeSubset, rect, gPrefColorType)) {
                     SkString subsetName = SkStringPrintf("%s-%s", filename, subsetDim.c_str());
@@ skipping 232 matching lines @@
     print_strings("Known failures", gKnownFailures);
 
     return failed ? -1 : 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif