Add graphics_WebGLManyPlanetsDeep test.

Also add the HTML and JavaScript source files (pulled from the public
khronos WebGL repository) to deps/webgl_mpd.

BUG=chromium:263300
TEST=test_that.py --fast <DUT IP> graphics_WebGLManyPlanetsDeep

Change-Id: Ia46664f89488cef6414c142e727e8e1e52522731
Reviewed-on: https://chromium-review.googlesource.com/57597
Reviewed-by: Ricky Liang <jcliang@chromium.org>
Commit-Queue: Ricky Liang <jcliang@chromium.org>
Tested-by: Ricky Liang <jcliang@chromium.org>
17 files changed