Revert of Cleanup and unify Isolate::ReportPendingMessages.

Revert of Cleanup and unify Isolate::ReportPendingMessages. (patchset #4 id:60001 of https://codereview.chromium.org/999923004/)

Reason for revert:
Failing Blink tests on Win and Mac:
- plugins/netscape-plugin-property-access-exception.html
- http/tests/plugins/cross-frame-object-access.html

Original issue's description:
> Cleanup and unify Isolate::ReportPendingMessages.
>
> Note that this is a pure cleanup CL and shouldn't have an observable
> impact on the functional behavior of message reporting.
>
> R=yangguo@chromium.org

TBR=yangguo@chromium.org,machenbach@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/0819ed9f33c1d74addd74b71b548032aa4dd5eaa
Cr-Commit-Position: refs/heads/master@{#27306}

[Michael Starzinger, 2015-03-19 13:22:25]

Created Revert of Cleanup and unify Isolate::ReportPendingMessages.

[commit-bot: I haz the power, 2015-03-19 13:22:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1016323002/1

[commit-bot: I haz the power, 2015-03-19 13:22:48]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-19 13:23:01]

Patchset 1 (id:??) landed as
https://crrev.com/0819ed9f33c1d74addd74b71b548032aa4dd5eaa
Cr-Commit-Position: refs/heads/master@{#27306}