Fixing crash in render_pictures when failing to create referenceBitmap for --validate

tools/render_pictures_main.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "CopyTilesRenderer.h"
 #include "SkBitmap.h"
 #include "SkBitmapFactory.h"
@@ skipping 145 matching lines @@
         SkDELETE(bitmap);
         return false;
     }
 
     if (FLAGS_validate) {
         SkBitmap* referenceBitmap = NULL;
         sk_tools::SimplePictureRenderer referenceRenderer;
         success = render_picture(inputPath, NULL, referenceRenderer,
                                  &referenceBitmap);
 
-        if (!success || !referenceBitmap) {
+        if (!success || NULL == referenceBitmap || NULL == referenceBitmap->getPixels()) {
             SkDebugf("Failed to draw the reference picture.\n");
             SkDELETE(bitmap);
             SkDELETE(referenceBitmap);
             return false;
         }
 
         if (success && (bitmap->width() != referenceBitmap->width())) {
             SkDebugf("Expected image width: %i, actual image width %i.\n",
                      referenceBitmap->width(), bitmap->width());
             SkDELETE(bitmap);
@@ skipping 146 matching lines @@
 #endif
 #endif
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif