Add a bitmap width and height size check to the PNG encoder

Source/platform/image-encoders/skia/PNGImageEncoder.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 103 matching lines @@
     return true;
 }
 
 bool PNGImageEncoder::encode(const SkBitmap& bitmap, Vector<unsigned char>* output)
 {
     SkAutoLockPixels bitmapLock(bitmap);
 
     if (bitmap.colorType() != kN32_SkColorType || !bitmap.getPixels())
         return false; // Only support 32 bit/pixel skia bitmaps.
 
+    if (bitmap.width() <= 0 || bitmap.height() <= 0)
+        return false; // crbug.com/504690
+
     return encodePixels(IntSize(bitmap.width(), bitmap.height()), static_cast<unsigned char*>(bitmap.getPixels()), true, output);
 }
 
 bool PNGImageEncoder::encode(const ImageDataBuffer& imageData, Vector<unsigned char>* output)
 {
     if (!imageData.pixels())
         return false;
 
     return encodePixels(IntSize(imageData.width(), imageData.height()), imageData.pixels(), false, output);
 }
 
 } // namespace blink