Rework NavigationHandle test interface

This CL removes many of the NavigationHandle test methods and introduces a
MockNavigationHandle class to use in tests instead. This is a preparatory CL to
have NavigationHandleImpl depend on NavigationRequest. Since NavigationRequest
is not a class that is exposed outside content, the testing structure where
content/ embedders create a NavigationHandle for testing cannot work anymore.

Change-Id: I85dd600bbf54a67d54185ac7a3c21be74d9ee694
Bug: 916537
Reviewed-on: https://chromium-review.googlesource.com/c/1367647
Commit-Queue: Camille Lamy <clamy@chromium.org>
Reviewed-by: Carlos Knippschild <carlosk@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Jan Krcal <jkrcal@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Nicolas Ouellet-Payeur <nicolaso@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Carlos IL <carlosil@chromium.org>
Reviewed-by: Christopher Thompson <cthomp@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Reviewed-by: Evan Stade <estade@chromium.org>
Reviewed-by: Ben Greenstein <bengr@chromium.org>
Reviewed-by: Nathan Parker <nparker@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620318}
41 files changed