[DevTools] Do not accept load drops.

BUG=341823

Review URL: https://codereview.chromium.org/157673004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250253 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250253
[Telemetry] Allow --netsim to work without running WPR with sudo

This is part of the effort to make Telemetry more bot and dev
friendly by eliminating dependencies on sudo.

With this change, we start the host WPR sever on ephemeral
ports and use iptables on the device to forward the true
ports to the WPR ports. It eliminates the need for all of
WPR to run as sudo.

BUG=

Review URL: https://codereview.chromium.org/134863005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250254 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250254