Add pep 435 summary entry in new required features, and ensurepip description.

Also added a note about platform packagers not being required to install
pip by default, if they provide an appropriate pip hook, to the PEP
description section.

Doc/whatsnew/3.4.rst

@@ -90,6 +90,7 @@ New syntax features:
 
 New expected features for Python implementations:
 
+* :ref:`pip should always be "available" <whatsnew-pep-453>` (:pep:`453`).
 * :ref:`Make newly created file descriptors non-inheritable <whatsnew-pep-446>`
   (:pep:`446`).
 * command line option for :ref:`isolated mode <using-on-misc-options>`,
@@ -146,6 +147,8 @@ sections on deprecations and porting issues.
 New expected features for Python implementations
 ================================================
 
+.. _whatsnew-pep-453:
+
 PEP 453: Explicit bootstrapping of pip in Python installations
 --------------------------------------------------------------
 
@@ -166,6 +169,12 @@ Makefile options.
 On Windows and Mac OS X, the CPython installers now offer the option to
 install ``pip`` along with CPython itself.
 
+As `discussed in the PEP`__, platform packagers may choose not to install
+``pip`` by default, as long as the command ``pip``, when invoked, provides
+clear and simple directions on how to install ``pip`` on the platform.
+
+__ http://www.python.org/dev/peps/pep-0453/#recommendations-for-downstream-distributors
+
 .. note::
 
    The implementation of PEP 453 is still a work in progress. Refer to
@@ -346,6 +355,31 @@ For Python 3.4, this module is considered a :term:`provisional API`.
    :pep:`3156` - Asynchronous IO Support Rebooted: the "asyncio" Module
       PEP written and implementation led by Guido van Rossum.
 
+
+.. _whatsnew-ensurepip
+
+ensurepip
+---------
+
+The new :mod:`ensurepip` module is the primary infrastructure for the
+:pep:`453` implementation.  In the normal course of events end users will not
+need to interact with this module, but it can be used to manually bootstrap
+``pip`` if the automated bootstrapping into an installation or virtual
+environment was declined.
+
+:mod:`ensurepip` includes a bundled copy of ``pip``, up-to-date as of the first
+release candidate of the release of CPython with which it ships (this applies
+to both maintenance releases and feature releases).  ``ensurepip`` does not
+access the internet.  (If the installation has Internet access, it is of course
+possible to upgrade ``pip`` to a release more recent than the bundled ``pip``
+by using the bundled ``pip`` command itself once it is installed.)
+
+The module is named *ensure*\ pip because if called when ``pip`` is already
+installed, it does nothing.  It also has an ``--upgrade`` option that will
+cause it to install the bundled copy of ``pip`` if the existing installed
+version of ``pip`` is older than the bundled copy.
+
+
 enum
 ----