services/ui: Initialize all of gpu in one thread.

The current code initializes GL, some of the gpu components (e.g.
GpuMemoryBufferFactory) in one thread, and then uses them in the gpu
thread. This is not correct, and causes some platforms to also crash.
So, move all of GL/gpu initializations into the dedicated gpu thread.

BUG=none

Review-Url: https://codereview.chromium.org/2366623002
Cr-Commit-Position: refs/heads/master@{#420974}
5 files changed