Mandoline: Implement basic "process per site" support

After fetching the resource, if it turns out it has a mime type that can
be handled by a known mojo app, then we grab the resources' URL, convert it
into a Site URL and use it as a qualifier to determine what process the mojo
app that will handle the resource should live in.

BUG=496937

Review URL: https://codereview.chromium.org/1229903003

Cr-Commit-Position: refs/heads/master@{#338317}


CrOS-Libchrome-Original-Commit: d75d12d0827be6d395ac851d37af4ba1ef78b60d
3 files changed
tree: 51a90f8dbdd9d9d7a180beb3a985715013d3f195
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/