Added a UMA metric to track slow path scrolling.

Added a UMA metric to track slow path scrolling.

Using a boolean UMA histogram to track slow scrolling so we know how
frequently it happens compared to fast scrolling gives a more complete
idea of what's going on.

BUG= #164083


Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=180051

[clholgat, 2013-01-29 21:30:04]

On 2013/01/22 22:57:13, Carson wrote:

Has anyone had a chance to look at this change?

[aelias_OOO_until_Jul13, 2013-01-29 22:00:08]

https://codereview.chromium.org/12035038/diff/1/cc/layer_tree_host_impl.cc
File cc/layer_tree_host_impl.cc (right):

https://codereview.chromium.org/12035038/diff/1/cc/layer_tree_host_impl.cc#ne...
cc/layer_tree_host_impl.cc:1182: UMA_HISTOGRAM_BOOLEAN("TryScroll.SlowScroll",
false);
Please put this one right before ScrollStarted since here it would trigger
multiple times if the scroll gets bubbled up through the layer tree.

[clholgat, 2013-01-31 18:55:50]

https://codereview.chromium.org/12035038/diff/1/cc/layer_tree_host_impl.cc
File cc/layer_tree_host_impl.cc (right):

https://codereview.chromium.org/12035038/diff/1/cc/layer_tree_host_impl.cc#ne...
cc/layer_tree_host_impl.cc:1182: UMA_HISTOGRAM_BOOLEAN("TryScroll.SlowScroll",
false);
On 2013/01/29 22:00:08, aelias wrote:
> Please put this one right before ScrollStarted since here it would trigger
> multiple times if the scroll gets bubbled up through the layer tree.

Done.

[aelias_OOO_until_Jul13, 2013-01-31 22:46:12]

lgtm

[aelias_OOO_until_Jul13, 2013-01-31 22:48:55]

[+jamesr, skyostil, rjkroege as FYI]

[commit-bot: I haz the power, 2013-01-31 22:59:48]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/clholgat@chromium.org/12035038/6001

[commit-bot: I haz the power, 2013-02-01 03:18:18]

Change committed as 180051