It is dangerous to ignore SkRect::intersect's return value

gm/gmmain.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.
  */
 
 /*
  * Code for the "gm" (Golden Master) rendering comparison tool.
  *
@@ skipping 686 matching lines @@
             return pdfDoc->close();
         } else {
             SkISize pageSize = gm->getISize();
             SkPDFDevice* dev = NULL;
             if (initialTransform.isIdentity()) {
                 dev = new SkPDFDevice(pageSize, pageSize, initialTransform);
             } else {
                 SkRect content = SkRect::MakeWH(SkIntToScalar(pageSize.width()),
                                                 SkIntToScalar(pageSize.height()));
                 initialTransform.mapRect(&content);
-                content.intersect(0, 0, SkIntToScalar(pageSize.width()),
-                                  SkIntToScalar(pageSize.height()));
+                if (!content.intersect(0, 0, SkIntToScalar(pageSize.width()),
+                                       SkIntToScalar(pageSize.height()))) {
+                    content.setEmpty();
+                }
                 SkISize contentSize =
                     SkISize::Make(SkScalarRoundToInt(content.width()),
                                   SkScalarRoundToInt(content.height()));
                 dev = new SkPDFDevice(pageSize, contentSize, initialTransform);
             }
             dev->setDCTEncoder(encode_to_dct_data);
             dev->setRasterDpi(SkIntToScalar(FLAGS_pdfRasterDpi));
             SkAutoUnref aur(dev);
             SkCanvas c(dev);
             invokeGM(gm, &c, true, false);
@@ skipping 1861 matching lines @@
     if (FLAGS_forceBWtext) {
         canvas->setDrawFilter(SkNEW(BWTextDrawFilter))->unref();
     }
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif