GitLab

Make VizCompositorThreadRunner into an abstract interface and move the
existing implementation to VizCompositorThreadRunnerImpl. Then add
VizCompositorThreadRunnerWebView which will be webview's entry point
into creating and establishing viz objects.

Add code paths to ContentGpuClient so that webview can optionally
override the default instance.

Currently VizCompositorThreadRunnerWebView doesn't do much, except it
uses TaskQueueViz and exposes a simple API to run and block for work on
viz while allowing viz to schedule tasks on the render thread.

Bug: 805739
Change-Id: Ic5d2c45666ebc1fc9381c8cd5c71b0de57dd0136
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731135Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: kylechar <kylechar@chromium.org>
Reviewed-by: Eric Karl <ericrk@chromium.org>
Commit-Queue: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683768}