Cleanup and unify Isolate::ReportPendingMessages.

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

[Yang, 2015-03-13 15:06:06]

On 2015/03/13 14:59:13, Michael Starzinger wrote:

Nice! LGTM if tests pass.

[Michael Starzinger, 2015-03-18 13:57:19]

The CQ bit was checked by mstarzinger@chromium.org

[Michael Starzinger, 2015-03-18 13:57:19]

The patchset sent to the CQ was uploaded after l-g-t-m from yangguo@chromium.org
Link to the patchset: https://codereview.chromium.org/999923004/#ps60001 (title:
"Simplify further.")

[commit-bot: I haz the power, 2015-03-18 13:57:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/999923004/60001

[commit-bot: I haz the power, 2015-03-18 15:59:58]

Patchset 4 (id:??) landed as
https://crrev.com/a8865b3bb1b30369051a7a305a1d09b746b23aad
Cr-Commit-Position: refs/heads/master@{#27276}

[commit-bot: I haz the power, 2015-03-18 16:02:02]

Committed patchset #4 (id:60001)

[Michael Achenbach, 2015-03-19 00:16:30]

machenbach@chromium.org changed reviewers:
+ machenbach@chromium.org

[Michael Achenbach, 2015-03-19 00:16:31]

Is it possible that this changed:
http://build.chromium.org/p/client.v8/builders/V8-Blink%20Mac/builds/2510
http://build.chromium.org/p/client.v8/builders/V8-Blink%20Win/builds/2653

Tests:
plugins/netscape-plugin-property-access-exception.html
http/tests/plugins/cross-frame-object-access.html

The problems are persistent and non-flaky. They don't show up on the blink
waterfall.

[Michael Achenbach, 2015-03-19 01:53:30]

Triggered a test here: https://codereview.chromium.org/1020733002/

[Michael Starzinger, 2015-03-19 13:22:24]

A revert of this CL (patchset #4 id:60001) has been created in
https://codereview.chromium.org/1016323002/ by mstarzinger@chromium.org.

The reason for reverting is: Failing Blink tests on Win and Mac:
- plugins/netscape-plugin-property-access-exception.html
- http/tests/plugins/cross-frame-object-access.html.