GitLab

Simplify PdfCompositorImplTest.

- Make OnCompositeToPdfCallback() a static method.
- Do not use std::move(map) when methods take the map by const-ref.
- Use C++11 map initialization syntax.

Change-Id: Ia6e9e1c5dd1074e8dd37a7d8c096a51aedf84161
Reviewed-on: https://chromium-review.googlesource.com/1167786Reviewed-by: Wei Li <weili@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581807}