Test decoding the bounds in skimage.

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 309 matching lines @@
                        SkImageDecoder::kDecodePixels_Mode)) {
         if (expect_to_fail(filename)) {
             gSuccessfulDecodes.push_back().appendf(
                 "failed to decode %s, which is a known failure.", srcPath);
         } else {
             gDecodeFailures.push_back().set(srcPath);
         }
         return;
     }
 
+    // Test decoding just the bounds. The bounds should always match.
+    {
+        stream.rewind();
+        SkBitmap dim;
+        if (!codec->decode(&stream, &dim, SkImageDecoder::kDecodeBounds_Mode)) {
+            SkString failure = SkStringPrintf("failed to decode bounds for %s", srcPath);
+            gDecodeFailures.push_back() = failure;
+        } else {
+            // Now check that the bounds match:
+            if (dim.width() != bitmap.width() || dim.height() != bitmap.height()) {
+                SkString failure = SkStringPrintf("bounds do not match for %s", srcPath);
+                gDecodeFailures.push_back() = failure;
+            }
+        }
+    }
+
     if (compare_to_expectations_if_necessary(bitmap, filename, &gDecodeFailures)) {
         gSuccessfulDecodes.push_back().printf("%s [%d %d]", srcPath, bitmap.width(),
                                               bitmap.height());
     } else if (!FLAGS_mismatchPath.isEmpty()) {
         SkString outPath;
         make_outname(&outPath, FLAGS_mismatchPath[0], srcPath, ".png");
         if (write_bitmap(outPath.c_str(), bitmap)) {
             gSuccessfulDecodes.push_back().appendf("\twrote %s", outPath.c_str());
         } else {
             gEncodeFailures.push_back().set(outPath);
@@ skipping 240 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