Revert of NaCl: Remove reliance on "init_done" SRPC call in the non-PNaCl case

Revert of NaCl: Remove reliance on "init_done" SRPC call in the non-PNaCl case (patchset #4 id:60001 of https://codereview.chromium.org/849523002/)

Reason for revert:
The change appears to cause NaClBrowserTestNewlib.Bad to become flaky.

The flakiness was reported in:
BUG=448596
Original change description:
> NaCl: Remove reliance on "init_done" SRPC call in the non-PNaCl case
>
> We can remove Plugin::NexeFileDidOpenContinuation(), which gets called
> via the "init_done" SRPC call (which calls
> StartupInitializationComplete() in plugin/service_runtime.cc).
>
> Its work gets done by the newer
> ManifestServiceProxy::StartupInitializationComplete() in
> components/nacl/renderer/ppb_nacl_private_impl.cc, which gets called
> via Chrome IPC (by the "PpapiHostMsg_StartupInitializationComplete"
> message).
>
> ppapi_dispatcher.cc: In order to keep the error handling tests in
> NaClBrowserTestNewlib.Bad passing, send the
> StartupInitializationComplete message earlier, before we call
> PPP_InitializeModule().  This ensures that crashes in
> PPP_InitializeModule() are reported properly.
>
> Note that PNaCl still relies on "init_done" for now.
>
> BUG=428030
> BUG=https://code.google.com/p/nativeclient/issues/detail?id=3864
>
> Committed: https://crrev.com/4c03d4d0964b0b69f5741aac6c78557b415617e1
> Cr-Commit-Position: refs/heads/master@{#311298}

BUG=428030
BUG=https://code.google.com/p/nativeclient/issues/detail?id=3864

Committed: https://crrev.com/ec66f0e4a143a1d87145e58258be1cc4d38c2f39
Cr-Commit-Position: refs/heads/master@{#311495}

[Mark Seaborn, 2015-01-14 06:16:13]

Created Revert of NaCl: Remove reliance on "init_done" SRPC call in the
non-PNaCl case

[Mark Seaborn, 2015-01-14 06:20:29]

Please review/rubber-stamp -- I don't intend to TBR this. :-)

[teravest, 2015-01-14 14:54:41]

lgtm

[Mark Seaborn, 2015-01-14 15:09:59]

The CQ bit was checked by mseaborn@chromium.org

[commit-bot: I haz the power, 2015-01-14 15:11:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/793723006/1

[commit-bot: I haz the power, 2015-01-14 16:56:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-14 16:56:55]

Patchset 1 (id:??) landed as
https://crrev.com/ec66f0e4a143a1d87145e58258be1cc4d38c2f39
Cr-Commit-Position: refs/heads/master@{#311495}