Revert of GC plugin: improve error reporting when tracing illegal fields. (patchset #2 id:20001 of https://codereview.chromium.org/2060553002/ )

Reason for revert:
New test fails: https://build.chromium.org/p/chromium.fyi/builders/ClangToTMac%20%28dbg%29/builds/5481/steps/gclient%20runhooks/logs/stdio

Original issue's description:
> GC plugin: improve error reporting when tracing illegal fields.
>
> Add detection of trace() calls over smart pointer types that either do not
> wrap up references to heap objects, or are otherwise not meant to be traced
> over. In particular, CrossThread(Weak)Persistent<T> fields are now detected
> as being illegal to trace over. Also consider OwnPtr<T>, RefPtr<T> and
> std::unique_ptr<T> as illegal to trace over & emit a more concise error
> messages for these.
>
> R=
> BUG=619149
>
> Committed: https://crrev.com/3ba6089cd6a901b62ff5a0d8f08a2bd818edcbe8
> Cr-Commit-Position: refs/heads/master@{#399861}

TBR=oilpan-reviews@chromium.org,sigbjornf@opera.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=619149

Review-Url: https://codereview.chromium.org/2068983003
Cr-Commit-Position: refs/heads/master@{#399868}
21 files changed