I originally just wanted to move the handle_ member from tcp_wrap and
pipe_wrap without changing its name. But I ran into an issue which I
believe is because tcp_wrap and pipe_wrap now extend ConnectionWrap.
Both classes are derived from StreamWrap which has an inheritance
tree that looks like this:

class PipeWrap : public StreamWrap, ConnectionWrap<PipeWrap, uv_pipe_t>
class StreamWrap : public HandleWrap, public StreamBase
class HandleWrap : public AsyncWrap
class AsyncWrap : public BaseObject

BaseObject has the following private member:
v8::Persistent<v8::Object> handle_;

The compiler complains that 'handle_' is found in multiple base classes
 of different types:

../src/pipe_wrap.cc:130:50: error:
member 'handle_' found in multiple base classes of different types
                 reinterpret_cast<uv_stream_t*>(&handle_),
                                                 ^
../src/base-object.h:47:30: note:
member found by ambiguous name lookup
  v8::Persistent<v8::Object> handle_;

It turns out that name lookup is performed before access rules are
considered.  C++ standard section 3.4:
"The access rules (Clause 11) are considered only once name lookup
and function overload resolution (if applicable) have succeeded."

It is possible to be explicit about the type you want using the
resolution operator ::. So we could use ConnectionWrap::handle_
to tell the compiler which type we want.

But going down this route still caused changes to a number of files
and I think the code is somewhat clearer using a different name for
the handle, and there is no confusion with the handle_ member in
BaseObject.

Being fairly new to C++ and to the project there this is probably a
gap in my knowledge about the best way to solve this. Looking forward
to hear about other options/ideas for this.

One of the issues in #4641 concerns OnConnection in pipe_wrap and
tcp_wrap which are very similar with some minor difference in how
they are coded. This commit extracts OnConnection so both these
classes can share the same implementation.

PR-URL: #7547
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

85af1a6 was added (squashed into another commit) without running
through CI. Unfortunately, it breaks some of the CI builds, notably on
three of the CentOS setups.

Undoing that one small change to get builds green again.

Refs: nodejs#7547 (comment)
PR-URL: nodejs#7873

85af1a6 was added (squashed into another commit) without running
through CI. Unfortunately, it breaks some of the CI builds, notably on
three of the CentOS setups.

Undoing that one small change to get builds green again.

Refs: nodejs#7547 (comment)
PR-URL: nodejs#7873
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Anna Henningsen <anna@addaleax.net>