scheduler: Avoid false alerts about expensive task blocking

scheduler: Avoid false alerts about expensive task blocking

This patch adjusts the logic for logging a console message when an
expensive task is blocked:

1. Don't log messages when all timer tasks are blocked (e.g., while
   waiting for a touchstart response). There's nothing the developer can
   do to avoid this type of blocking.

2. Only report blocking for tasks which exceed the 50ms RAIL threshold.
   These types of tasks are most likely to cause user visible jank.
   Lower blocking thresholds are also used for shorter periods of time,
   so shorter tasks are not likely to be deferred for a long time
   in any case.

3. Also mention network tasks in the log message.

BUG=613230
Review-Url: https://codereview.chromium.org/2016943003
Cr-Commit-Position: refs/heads/master@{#396467}
(cherry picked from commit c66723959e9a37f1a5bbd821366a2ee24a9537c2)

Committed: https://chromium.googlesource.com/chromium/src/+/72912f97a2fd244ce81b7720694fa34a159d8b22

[Sami, 2016-05-31 09:27:34]

Description was changed from

==========
scheduler: Avoid false alerts about expensive task blocking

This patch adjusts the logic for logging a console message when an
expensive task is blocked:

1. Don't log messages when all timer tasks are blocked (e.g., while
   waiting for a touchstart response). There's nothing the developer can
   do to avoid this type of blocking.

2. Only report blocking for tasks which exceed the 50ms RAIL threshold.
   These types of tasks are most likely to cause user visible jank.
   Lower blocking thresholds are also used for shorter periods of time,
   so shorter tasks are not likely to be deferred for a long time
   in any case.

3. Also mention network tasks in the log message.

BUG=613230

Review-Url: https://codereview.chromium.org/2016943003
Cr-Commit-Position: refs/heads/master@{#396467}
(cherry picked from commit c66723959e9a37f1a5bbd821366a2ee24a9537c2)
==========

to

==========
scheduler: Avoid false alerts about expensive task blocking

This patch adjusts the logic for logging a console message when an
expensive task is blocked:

1. Don't log messages when all timer tasks are blocked (e.g., while
   waiting for a touchstart response). There's nothing the developer can
   do to avoid this type of blocking.

2. Only report blocking for tasks which exceed the 50ms RAIL threshold.
   These types of tasks are most likely to cause user visible jank.
   Lower blocking thresholds are also used for shorter periods of time,
   so shorter tasks are not likely to be deferred for a long time
   in any case.

3. Also mention network tasks in the log message.

BUG=613230

Review-Url: https://codereview.chromium.org/2016943003
Cr-Commit-Position: refs/heads/master@{#396467}
(cherry picked from commit c66723959e9a37f1a5bbd821366a2ee24a9537c2)

Committed:
https://chromium.googlesource.com/chromium/src/+/72912f97a2fd244ce81b7720694f...
==========

[Sami, 2016-05-31 09:27:35]

Committed patchset #1 (id:1) manually as
72912f97a2fd244ce81b7720694fa34a159d8b22.