GitLab

Prior to this change, WebContentsTaskProvider would defer task creation if the
PID was not known at RenderFrameCreated time. However, for a newly-cloned
WebContents, no event ever occurred to re-create the Task once the process
finished launching. This was bug 738169.

Fix the problem by never deferring task_manager::Task creation; instead, create
Tasks for all live, current RenderFrameHosts. If the PID is not known immediately,
allow it to be set on the task at a later time (when RenderProcessHost::IsReady()
becomes true).

Because the TaskManagerImpl was written with the expectation that Tasks have
a constant PID, PID mutation is implemented in terms of temporarily removing the
task, mutating the PID, and re-adding it.

In WebContentsTaskProvider, we no longer need to implement RenderProcessGone.

In TaskGroup, don't waste time collecting stats for a null process ID.

Tests are added exercising this bug, and its subframe equivalent. Test coverage
is added for the PID==0 case, and we ensure that the "Memory" column is
populated with something nonzero.

BUG=738169

Review-Url: https://codereview.chromium.org/2961423002
Cr-Commit-Position: refs/heads/master@{#491180}