tree 3acdf923c475b741211cff1c9f8cfcc818796674
parent 39e1fa0c4cc6e925c758056b01a6d4686151708f
author Erwin Jansen <jansene@google.com> 1612661108 -0800
committer Yahan Zhou <yahan@google.com> 1672781047 -0800

Simplify frame callback pipeline.

The gRPC streamScreenshot api works roughly as follows:

1. Register for frame change events.
2. Take a screenshot when event is received.
3. Send screenshot to client

Previously we used the callback infrastructure used by screen recording.
This callback mechanism provides the frame that was produced as well,
and introduced a significant amount of overhead that could result in
screen flicker when there is a consistent high FPS. Note that the
returned frame was never used by the gRPC api.

We now introduce a lightweight callback that only notifies that a new
frame is available, and no longer copy around frames.

Bug: b/179310324
Test: No more flickering in fuchsia when streaming screenshots.
Change-Id: Ibd63f7fcaa4228466dd6d13877b5793d8f6f8444