Make SyncSessionsWebContentsRouterTest a ChromeRenderViewHostTestHarness

This simplifies the test fixture and allows the tests to pass in
single process mash.

(Technically, they also pass in single process mash without this change,
but would cease to do so after AuraTestSuite stops creating an
InputDeviceClient, which will soon happen.)

Bug: 905430
Change-Id: I9536989b016176b96db824732720b86d6442f27d
Reviewed-on: https://chromium-review.googlesource.com/c/1343338
Commit-Queue: Evan Stade <estade@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609776}
1 file changed