[NaClSDK] Docs: Fix another manifest "typo" w/ portable dict.

native_client_sdk/src/doc/devguide/devcycle/debugging.rst

 .. _devcycle-debugging:
 
 #########
 Debugging
 #########
 
 This document describes tools and techniques you can use to debug, monitor,
 and measure your application's performance.
 
 .. contents:: Table Of Contents
@@ skipping 227 matching lines @@
 debugging (this is more of a problem with the PNaCl/LLVM toolchain than
 with GCC).
 
 Once you have built a non-stable debug copy of the pexe, list the URL of
 that copy in your application's manifest file:
 
 .. naclcode::
 
   {
     "program": {
-      "pnacl-translate": {
-        "url": "release_version.pexe",
-        "optlevel": 2
-      },
-      "pnacl-debug": {
-        "url": "debug_version.bc",
-        "optlevel": 0
+      "portable": {
+        "pnacl-translate": {
+          "url": "release_version.pexe",
+          "optlevel": 2
+        },
+        "pnacl-debug": {
+          "url": "debug_version.bc",
+          "optlevel": 0
+        }
       }
     }
   }
 
 Copy the ``debug_version.bc`` and ``nmf`` files to the location that
 your local web server serves files from.
 
 When you run Chrome with ``--enable-nacl-debug``, Chrome will translate
 and run the ``debug_version.bc`` instead of ``release_version.pexe``.
 Once the debug version is loaded, you are ready to :ref:`run nacl-gdb
@@ skipping 323 matching lines @@
 <http://www.chromium.org/nativeclient>`_ that describe how to do profiling on
 `64-bit Windows
 <https://sites.google.com/a/chromium.org/dev/nativeclient/how-tos/profiling-nacl-apps-on-64-bit-windows>`_
 and `Linux
 <http://www.chromium.org/nativeclient/how-tos/limited-profiling-with-oprofile-on-x86-64>`_
 machines.
 
 
 .. |menu-icon| image:: /images/menu-icon.png
 .. |puzzle| image:: /images/puzzle.png