NaCl: Remove now-unneeded SRPC reverse service code

NaCl: Remove now-unneeded SRPC reverse service code

The last active use of PluginReverseInterface was via its
StartupInitializationComplete()/"init_done" method, but recent
cleanups have made that into a no-op.

We can therefore remove PluginReverseInterface.  We no longer need to
call NaCl's "reverse_setup" SRPC call.

This removes the Chromium-side parts of the old SRPC-based
open_resource() implementation, which was no longer called.  This
allows us to remove OpenManifestEntry() from PPB_NaCl_Private.

Add some #includes to fix include-what-you-use problems that become
apparent after removing code.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3864
TEST=NaCl tests in browser_tests

Committed: https://crrev.com/99fa53e6d838abd24d690a748b09b03420dfc1ce
Cr-Commit-Position: refs/heads/master@{#312953}

[Mark Seaborn, 2015-01-23 16:57:16]

mseaborn@chromium.org changed reviewers:
+ teravest@chromium.org

[teravest, 2015-01-23 17:08:31]

lgtm

[Mark Seaborn, 2015-01-23 22:38:50]

The CQ bit was checked by mseaborn@chromium.org

[commit-bot: I haz the power, 2015-01-23 22:40:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/870923004/20001

[commit-bot: I haz the power, 2015-01-23 22:50:57]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-01-23 22:52:05]

Patchset 2 (id:??) landed as
https://crrev.com/99fa53e6d838abd24d690a748b09b03420dfc1ce
Cr-Commit-Position: refs/heads/master@{#312953}