Revert of Make WebTraceLocation be an alias of tracked_objects::Location

Revert of Make WebTraceLocation be an alias of tracked_objects::Location (patchset #6 id:100001 of https://codereview.chromium.org/2137013002/ )

Reason for revert:
Speculative revert: this CL may regress  system_health.memory_mobile benchmark

BUG=629112
Original issue's description:
> Make WebTraceLocation be an alias of tracked_objects::Location
> 
> Make WebTraceLocation be an alias of tracked_objects::Location and
> BLINK_FROM_HERE be an alias of FROM_HERE as well. So that tasks posted
> from Blink leaves a valid program counter and line number in the crash
> dump.
> 
> Committed: https://crrev.com/3c109dd65c1984237444da93f7c7acc8b0bdcd92
> Cr-Commit-Position: refs/heads/master@{#405736}

TBR=esprehn@chromium.org,alexclarke@chromium.org,kinuko@chromium.org,tkent@chromium.org,tzik@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.

[nednguyen, 2016-08-05 20:03:53]

The CQ bit was checked by nednguyen@google.com

[nednguyen, 2016-08-05 20:03:54]

Created Revert of Make WebTraceLocation be an alias of tracked_objects::Location

[commit-bot: I haz the power, 2016-08-05 20:04:20]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-05 20:06:36]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-08-05 20:06:37]

Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[esprehn, 2016-08-05 20:52:29]

This patch is so old, I suspect you'd need to manually revert.