Delete unneeded pending entries in DidFailProvisionalLoad to prevent a spoof.

BUG=280512
BUG=278899
TEST=See bug for repro steps.

Review URL: https://chromiumcodereview.appspot.com/23978003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@222146 0039d316-1c4b-4281-b951-d872f2087c98
gfx::Image CreateImage(SkColor color) {
  SkBitmap bitmap;
  bitmap.setConfig(SkBitmap::kARGB_8888_Config, 1, 1);
  bitmap.allocPixels();
  bitmap.eraseColor(color);
  return gfx::Image::CreateFrom1xBitmap(bitmap);
}

gfx::Image CreateImage(SkColor color) {
  SkBitmap bitmap;
  bitmap.setConfig(SkBitmap::kARGB_8888_Config, 1, 1);
  bitmap.allocPixels();
  bitmap.eraseColor(color);
  return gfx::Image::CreateFrom1xBitmap(bitmap);
}
