The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/50a635ebbf250f8f35ea060d564b102b804dcea7

commit 50a635ebbf250f8f35ea060d564b102b804dcea7
Author: sandersd <sandersd@chromium.org>
Date: Mon Apr 04 22:50:09 2016

Convert WMPI state management to level-triggered.

Calling NotifyPlaybackStarted()/NotifyPlaybackPaused() at the correct
times has been a recurring source of bugs. This change moves all of the
logic to a single method, which will hopefully be easier to understand
and debug.

This new method handles delegate state, suspend/resume, and the memory
usage reporting timer together in one place. It's not simple, but it is
commented liberally.

The new suspend/resume logic does not rely on the suspend/resume
callbacks (instead it's only based on the goal state, never the current
state). As a result I was also able to remove the resume callback from
PipelineController in this CL.

BUG=595900, 597692 

Review URL: https://codereview.chromium.org/1830913005

Cr-Commit-Position: refs/heads/master@{#385038}

[modify] https://crrev.com/50a635ebbf250f8f35ea060d564b102b804dcea7/media/blink/webmediaplayer_impl.cc
[modify] https://crrev.com/50a635ebbf250f8f35ea060d564b102b804dcea7/media/blink/webmediaplayer_impl.h
[modify] https://crrev.com/50a635ebbf250f8f35ea060d564b102b804dcea7/media/blink/webmediaplayer_impl_unittest.cc
[modify] https://crrev.com/50a635ebbf250f8f35ea060d564b102b804dcea7/media/filters/pipeline_controller.cc
[modify] https://crrev.com/50a635ebbf250f8f35ea060d564b102b804dcea7/media/filters/pipeline_controller.h
[modify] https://crrev.com/50a635ebbf250f8f35ea060d564b102b804dcea7/media/filters/pipeline_controller_unittest.cc

This issue has been available for more than 365 days, and should be re-evaluated. Please re-triage this issue.
The Hotlist-Recharge-Cold label is applied for tracking purposes, and should not be removed after re-triaging the issue.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

I disagree and think we'll always need these on suspend / on resume method.

If that's true, then we should design a better mechanism. The suspended/resumed callbacks are vulnerable to re-entrancy bugs in a way that the other callbacks are not.

Re-opening with new description.

It is not safe to call PipelineController methods from OnPipelineSuspended, OnBeforePipelineResumed, or OnPipelineResumed. Since it's easy for reviewers to miss changes that violate this rule, a safer mechanism should be designed.