Introduce a mojo method to send renderer debug URLS to the renderer

This CL introduces a mojo method to send renderer debug URLS to the renderer
for handling, instead of using CommitNavigation. This allows not to create a
NavigationRequest nor a NavigationHandle for these URLs, which do not represent
actual navigations.

Bug: 784904,803859
Change-Id: Ica9b17a071d2f9faa7f43eb428b0d73424a180e9
Reviewed-on: https://chromium-review.googlesource.com/817560
Reviewed-by: Charlie Reis <creis@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Commit-Queue: Camille Lamy <clamy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533719}
17 files changed