Don't use a sleep in the browser's main thread to throttle swapbuffers.

Don't use a sleep in the browser's main thread to throttle swapbuffers.

Throttle by delaying sending the ack of each frame to the renderer until
a vsync interval has passed since the last ack was sent.

Explicitly disable throttling when threaded compositing is enabled (it
was supposed to not kick in because the thread proxy will not send new
frames more than once per vsync).

Also move informing the renderer of the vsync properties to be
immediate (not delayed with the ack) and only send this data when
a new frame has been sent (not every time all acks are cleared).
This should not have any material impact, and is to make the flow
easier to follow.

BUG=245900
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=206338

[ccameron, 2013-06-12 22:38:23]

This re-visits the change in
https://chromiumcodereview.appspot.com/10828104

I plan to remove the vsync info from CompositingIOSurface and put it in its own
structure, but that can wait.

This impacts non-threaded compositing, which includes all Macs running 10.6 and
10.7 (see https://codereview.chromium.org/12225103).

[Ken Russell (switch to Gerrit), 2013-06-12 23:10:47]

LGTM -- this seems like a very good change.

[ccameron, 2013-06-12 23:33:23]

Thanks!!

[commit-bot: I haz the power, 2013-06-14 01:48:56]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ccameron@chromium.org/16845005/9001

[commit-bot: I haz the power, 2013-06-14 02:11:49]

Sorry for I got bad news for ya.
Compile failed with a clobber build on ios_rel_device.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=ios_rel_de...
Your code is likely broken or HEAD is junk. Please ensure your
code is not broken then alert the build sheriffs.
Look at the try server FAQ for more details.

[commit-bot: I haz the power, 2013-06-14 04:01:12]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ccameron@chromium.org/16845005/9001

[commit-bot: I haz the power, 2013-06-14 06:47:33]

Change committed as 206338