Prime the landing pad for the new video rendering pipeline.

This is not a functional change, it only updates the interfaces and
call sites in preparation for switching to a vsync based video
rendering pipeline.

Some notes:
- Plumbs a VideoRendererSink into the the rendering pipeline; similar to
how we have an AudioRendererSink.
- A couple VideoRendererSink mocks are introduced which will be short
lived. Like audio, we will need fakes which can pump consumption tasks.
- The "PaintCB" callback has been temporarily placed on the new sink
interface such that in the field experiments can be run comparing the
performance of the video rendering approaches.
- Finally nukes Player_X11 since setting up a vsync renderer just for
unused tool code isn't worth the effort.
- Since compositor callbacks may stop due to visibility changes, the
new VideoRendererImpl will use a countdown timer to pump video playback
as frames expire; expired frames will not count as dropped.
- Since canvas/WebGL requires frame updates in the background a new
method has been added to VideoFrameCompositor to return the current
frame if it was updated with 250ms, or to request a new one and return
the updated one.

Subsequent work:
- sunnyps@ will be switching VideoFrameProviderClientImpl over to using
a BeginFrameObserver, which will ultimately drive the Render() callbacks.
- dalecurtis@ will land the VideoRendererAlgorithm which powers the new
rendering pipeline.

BUG=439548
TEST=everything works as is.

Review URL: https://codereview.chromium.org/1053113002

Cr-Commit-Position: refs/heads/master@{#325306}

1 files changed, 0 insertions, 1 deletions

diff --git a/BUILD.gn b/BUILD.gn
index cf1bd2b..b51ff78 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -469,7 +469,6 @@ group("gn_all") {
     }
 
     if (use_x11) {
-      deps += [ "//media:player_x11" ]
       if (target_cpu != "arm") {
         deps += [ "//gpu/tools/compositor_model_bench" ]
       }