This reverts commit c34042cc.

Reason for revert: Wrong table type was used

Original change's description:
> [heap-profiler] Do not treat WeakMap values as weak.
> 
> For the WeakHashTable objects only mark keys as weak while leaving values as strong references.
> 
> BUG=chomium:773722
> 
> Change-Id: Iabd5ba293d05fe68a2af6503fcdd711ecc182482
> Reviewed-on: https://chromium-review.googlesource.com/730771
> Commit-Queue: Alexei Filippov <alph@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48985}

TBR=ulan@chromium.org,alph@chromium.org,mlippautz@chromium.org

Change-Id: Ia2ddef5b2422d4cbb8c4710e24ed0885a9a5b284
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chomium:773722
Reviewed-on: https://chromium-review.googlesource.com/740721Reviewed-by: Alexei Filippov <alph@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48986}