Prevent delegated ink on unsupported renderers from crashing the gpu

Currently, delegated ink trails are only supported on the Skia Renderer,
so when we try to create a DelegatedInkPointRenderer only the Skia
Renderer will actually create it. So when we create that, then
immediately try to initialize it in Display, if we aren't on the
Skia Renderer we end up with an access violation and crashing the gpu
process.

This change adds a null check on the DelegatedInkPointRenderer before
trying to initialize it, and adds tests to confirm that delegated ink
silently fails on unsupported renderers.

I also added a null check for |output_surface_| for the platform
delegated ink path - this isn't a crash we were seeing, but it seems
reasonable to add to be safe. Some places in Display check it before
using it, others do not.

Bug: 1223175
Change-Id: I57fdf029cbcb33e0ef32701b1af92db4f5aa97d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2983340
Reviewed-by: weiliangc <weiliangc@chromium.org>
Commit-Queue: Mario Bianucci <mabian@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#895706}