Refactoring: Split NaClListener into two delegated classes.

components/nacl.gyp

Index: components/nacl.gyp
diff --git a/components/nacl.gyp b/components/nacl.gyp
index a9933cad5a19654dd229878f17971b3772c0bd89..123fdef8f045d57abfcb41fd1e7e4e3594a82468 100644
--- a/components/nacl.gyp
+++ b/components/nacl.gyp
@@ -27,6 +27,7 @@
           # .cc, .h, and .mm files under nacl that are used on all
           # platforms, including both 32-bit and 64-bit Windows.
           # Test files are also not included.
+          'nacl/loader/listener_delegate.h',

[Mark Seaborn, 2014/08/07 00:50:20]

Nit: doesn't follow the "nacl_*" naming scheme.  The existing naming scheme is a
bit redundant, but... maybe you could just declare the delegate base class in
nacl_listener.h?

           'nacl/loader/nacl_ipc_adapter.cc',
           'nacl/loader/nacl_ipc_adapter.h',
           'nacl/loader/nacl_main.cc',
@@ -41,6 +42,8 @@
           'nacl/loader/nacl_validation_db.h',
           'nacl/loader/nacl_validation_query.cc',
           'nacl/loader/nacl_validation_query.h',
+          'nacl/loader/sfi_listener_delegate.cc',

[Mark Seaborn, 2014/08/07 00:50:20]

Hmm, using "sfi_" would be a new naming scheme.  Other stuff is SFI-only too. 
It might be confusing to change the naming scheme piecemeal.

Can we just call this "loader/nacl_listener_delegate.cc" for consistency with
existing code?

+          'nacl/loader/sfi_listener_delegate.h',
         ],
         # TODO(gregoryd): consider switching NaCl to use Chrome OS defines
         'conditions': [
@@ -238,6 +241,8 @@
               'sources': [
                 'nacl/loader/nacl_helper_linux.cc',
                 'nacl/loader/nacl_helper_linux.h',
+                'nacl/loader/nonsfi_listener_delegate.cc',

[Mark Seaborn, 2014/08/07 00:50:20]

Shouldn't this go in the loader/nonsfi/ subdir for consistency with the existing
nonsfi code?  e.g. as "loader/nonsfi/nonsfi_listener_delegate.cc"

+                'nacl/loader/nonsfi_listener_delegate.h',
               ],
               'dependencies': [
                 'nacl_linux',