This isn't a patch but one possible solution. I wrote a wrapper for WWW::Mechanize::Chrome in Moose. Note that that get method is overridden. Every 1/10th of a second it checks to see if new elements have been loaded on the page. If there were, it waits another 1/10th of a second. The length of time can be increased for slower connections.

package WWW::Mechanize::Chrome::MooseWrapper ;

use Moose;
use MooseX::NonMoose;
use Time::HiRes qw(usleep);
use File::Temp 'tempdir';
use Log::Log4perl qw(:easy);
use Data::Dumper qw(Dumper);
use namespace::autoclean;
extends 'WWW::Mechanize::Chrome';

sub FOREIGNBUILDARGS {
  my $class = shift;
  my %args = ( @_ == 1 ? %{ $_[0] } : @_);

  # set default launch args
  $args{launch_exe}     = $args{launch_exe}       || "/Applications/Go
+ogle Chrome.app/Contents/MacOS/Google Chrome";
  $args{launch_arg}     = $args{launch_arg}       || [ '--disable-noti
+fications' ];
  $args{data_directory} = $args{data_directory}   || tempdir();
  $args{incognito}      = exists $args{incognito}  ? $args{incognito} 
+: 1;
  return %args;
}

### Public methods ###

sub scroll_to_bottom {
  my $s = shift;
  $s->eval( 'window.scroll(0,document.body.scrollHeight)' );
}

sub scroll_to_top {
  my $s = shift;
  $s->eval( 'window.scroll(0,0)' );
}

sub get_element_count {
  my $s = shift;
  my ($el_count) = $s->eval( 'document.getElementsByTagName("*").lengt
+h' );
  return $el_count;
}

around get => sub {
  my $orig = shift;
  my $s = shift;
  my $url = shift;
  $s->SUPER::get($url);
  my $el_count = $s->get_element_count;

  # wait 1/10th sec for more of the page to load
  usleep 100000;

  while ($el_count != $s->get_element_count) {
    # wait 1/10th sec for more of the page to load
    usleep 100000;
    $el_count = $s->get_element_count;
  }
};



### Private methods ###


__PACKAGE__->meta->make_immutable;
1; # Magic true value
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