cc: Add command line for frame production throttle.

This CL decouples "disable gpu vsync" and "throttle frame production".

1. Add options of display-gpu-vsync
--disable-gpu-vsync=gpu :  Sets |disable_display_vsync| true.
--disable-gpu-vsync=beginframe : Sets |throttle_frame_production| false.
--disable-gpu-vsync : Same as using both flags above.

2. Rename |disable_gpu_vsync| variable to |disable_display_vsync|.

BUG=492732
R=brianderson@chromium.org, sky@chromium.org, danakj@chromium.org, jam@chromium.org
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1177383005

Cr-Commit-Position: refs/heads/master@{#338800}
11 files changed