Revert of [tracing] Simplify logic of MemoryDumpManager (patchset #9 id:160001 of https://codereview.chromium.org/1536533004/ )
Reason for revert:
Caused crash in pending-version-change-stuck-works-with-terminate.html layout test.
See:
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac10.10/builds/9506/steps/webkit_tests/logs/stdio
Original issue's description:
> [tracing] Simplify logic of MemoryDumpManager
>
> This CL simplifies the unregistration logic of MemoryDumpManager.
> This is to make the overall code more readable and simplify upcoming
> changes.
> Prior to this CL, the MemoryDumpManager was keeping only one list to
> keep track of the registered dump providers. This caused the
> unregistration logic to be tricky because:
> - We couldn't remove the MDPInfo straight away, as that might
> cause invalidation of the |next_dump_provider| iterator.
> - We had to flag the MDPInfo as unregistered and postpone the deletion
> on the next dump.
> This has a major drawback: if we keep registering and unregistering
> dump providers when no tracing is happening at all, the dump_providers_
> list grows without bounds. This is bad.
>
> This CL changes the logic as follows:
> - MDPInfo becomes refcounted. At any time it can be referenced by:
> - The MDM's |dump_providers_| list.
> - The |ProcessMemoryDumpAsyncState.pending_dump_providers| list.
> - Upon each dump, the dump provider list is snapshotted in the
> |ProcessMemoryDumpAsyncState.pending_dump_providers|
> - Upon unregistration of a dump provider we just remove the MDPInfo
> from the MDM's |dump_providers_|. If a dump is ongoing, the
> ProcessMemoryDumpAsyncState will keep it refcounted and delete it
> during the dump.
>
> This CL does not add or change any behavior of the MemoryDumpManager,
> with the exception of:
> - Fixing a corner case when dumping with no dump providers registered
> (See changes in the unittest).
> - Making the fail-safe logic more strict: if a dumper fails once, it
> will stay disabled forever.
>
> BUG=461788
>
> Committed: https://crrev.com/9734733909e7cb41ef5c153f3c2d0927e8209133
> Cr-Commit-Position: refs/heads/master@{#366374}
TBR=ruuda@google.com,ssid@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=461788
Review URL: https://codereview.chromium.org/1540283003
Cr-Commit-Position: refs/heads/master@{#366386}
CrOS-Libchrome-Original-Commit: 6a7365c4c5ad3e3083ce3d9a269c3e1d8fdb35bc
3 files changed