aw: Change telemetry traces to collect better startup time stats.

aw: Change telemetry traces to collect better startup time stats.

1) Time new WebView + setContentView - this tests how an app that
   has a WebView in its layout will be affected.
2) Time the full time from new WebView to onPageFinished. This
   allows us to know if we regress something that happens
   asynchronously on startup that blocks URL loading.

BUG=

Committed: https://crrev.com/c73f1c265e7a8e61e280a0dfa53f826f08b548c4
Cr-Commit-Position: refs/heads/master@{#422798}

[Tobias Sargeant, 2016-09-29 14:41:01]

tobiasjs@chromium.org changed reviewers:
+ perezju@chromium.org, torne@chromium.org

[Torne, 2016-09-29 15:29:05]

LGTM. I assume we need to update something to track the new trace tag, and we
need to be aware that this will cause a jump in WebViewStartupInterval since
it's measuring a longer period now. :)

[perezju, 2016-09-29 15:38:47]

perezju@chromium.org changed reviewers:
+ alexandermont@chromium.org

[perezju, 2016-09-29 15:38:47]

rs-lgtm, but keep alexandermont in the loop. Will this need a change on the
metrics side?

[Tobias Sargeant, 2016-09-29 15:40:25]

On 2016/09/29 15:38:47, perezju wrote:
> rs-lgtm, but keep alexandermont in the loop. Will this need a change on the
> metrics side?

I guess we will want to add tracking for the overall trace time.

[Tobias Sargeant, 2016-10-04 15:01:08]

The CQ bit was checked by tobiasjs@chromium.org

[commit-bot: I haz the power, 2016-10-04 15:01:38]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-04 15:11:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-04 15:13:49]

Description was changed from

==========
aw: Change telemetry traces to collect better startup time stats.

1) Time new WebView + setContentView - this tests how an app that
   has a WebView in its layout will be affected.
2) Time the full time from new WebView to onPageFinished. This
   allows us to know if we regress something that happens
   asynchronously on startup that blocks URL loading.

BUG=
==========

to

==========
aw: Change telemetry traces to collect better startup time stats.

1) Time new WebView + setContentView - this tests how an app that
   has a WebView in its layout will be affected.
2) Time the full time from new WebView to onPageFinished. This
   allows us to know if we regress something that happens
   asynchronously on startup that blocks URL loading.

BUG=

Committed: https://crrev.com/c73f1c265e7a8e61e280a0dfa53f826f08b548c4
Cr-Commit-Position: refs/heads/master@{#422798}
==========

[commit-bot: I haz the power, 2016-10-04 15:13:50]

Patchset 1 (id:??) landed as
https://crrev.com/c73f1c265e7a8e61e280a0dfa53f826f08b548c4
Cr-Commit-Position: refs/heads/master@{#422798}