Revert of [tracing] Fix, simplify and speed up accounting of TraceEvent memory overhead (patchset #4 id:60001 of https://codereview.chromium.org/1251203003/ )

Reason for revert:
Speculative revert for https://code.google.com/p/chromium/issues/detail?id=516056

Original issue's description:
> [tracing] Fix, simplify and speed up accounting of TraceEvent memory overhead
>
> So far the accounting of TraceEvent memory overhead worked as follows:
>  - Each TraceEvent keeps a cache of its own overhead.
>  - The TraceBufferChunk (which is approx an array of 64 TraceEvent)
>    keeps a cache of the all 64 TraceEvent, but only when completelly
>    filled.
>
> This is sub-optimal because:
>  - There can be many TraceEvent(s), 10k-100k in a bulky 30s trace:
>    when memory-infra is enabled, this causes a cost of several MB to
>    keep the aforementioned per-TraceEvent caches.
>  - Every time we have to estimate the size of a non-completely-full
>    TraceBufferChunk, we still have to loop over their individual caches.
>  - Least but not last, turns out that the current accounting is just
>    wrong, as we ended up counting the sizeof(TraceEvent) both in
>    TraceBufferChunk and in the individual TraceEvent.
>
> This CL improves the situation as follows:
>  - The per-TraceEvent cache is dropped. Much less memory is used.
>  - The TraceBufferChunk still keeps a cache, but its cache is used in a
>    smarter way and not just when it is full. We simply remember how many
>    TraceEvent(s) we estimated in the previous pass and then estimate just
>    the missing ones.
>  - The double accounting issue is fixed, as now we count TraceEvent(s)
>    only in TraceBufferChunk.
>
> BUG=512383
>
> Committed: https://crrev.com/b2ae97fb331cbad132a8e1aad9a25441fde75048
> Cr-Commit-Position: refs/heads/master@{#340005}

TBR=dsinclair@chromium.org,primiano@chromium.org
BUG=512383

Review URL: https://codereview.chromium.org/1258903003

Cr-Commit-Position: refs/heads/master@{#341910}


CrOS-Libchrome-Original-Commit: 8f329fc15f5fa64f64308244266a304c122a2868
6 files changed
tree: 9f2a2040b48cb5b79bea0c1d524e445b3b6f2de0
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/