Use a more common and easily parsed format for chrome://fileicon

Instead of using custom dir/like/things, let's use the more standard:

  ?param1=val1&param2=val2

Because it allows us to use URLSearchParams[1] in JS:

  url.searchParams.set('param1', 'val1');

And net::QueryIterator in C++:

  for (net::QueryIterator it(url); !it.IsAtEnd(); it.Advance()) {
    // use it.GetKey() and it.GetValue()
  }

R=dpapad@chromium.org
BUG=953962

[1] https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams

Change-Id: I708ae3349d826793b5d1dbd6e1c1683e08ce254e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1574373
Commit-Queue: Dan Beam <dbeam@chromium.org>
Auto-Submit: Dan Beam <dbeam@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652739}
6 files changed