Revert of PPAPI: Never re-enter JavaScript for PostMessage. (patchset #5 id:80001 of https://codereview.chromium.org/
589213003/)
Reason for revert:
Still causing a crash in Canary
Original issue's description:
> PPAPI: Never re-enter JavaScript for PostMessage.
>
> Blocking renderer->plugin messages can be interrupted by any message
> from the plugin->renderer (even async ones). So while handline a blocking
> message, such as HandleInputEvent or HandleBlockingMessage, it's currently
> possible to re-enter JavaScript. This patch makes that impossible by
> queueing up Plugin->Renderer messages sent via PPB_Messaging::PostMessage
> while any renderer->plugin sync message is on the stack.
>
> BUG=384528
>
> Committed: https://crrev.com/
f73075c99b5ba30e8d62dc5f13fdfb210d0fc506
> Cr-Commit-Position: refs/heads/master@{#296311}
>
> Committed: https://crrev.com/
3fe4ceee750b2cd130bd402de3d371d8518c3eba
> Cr-Commit-Position: refs/heads/master@{#296807}
TBR=raymes@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=384528
Review URL: https://codereview.chromium.org/
605393002
Cr-Commit-Position: refs/heads/master@{#297030}