Per P0 reqs add launch pts + make download obvious. Also misc cpy edits.

native_client_sdk/src/doc/devguide/coding/file-io.rst

 .. _devguide-coding-fileio:
 
 ########
 File I/O
 ########
 
 .. contents::
   :local:
   :backlinks: none
   :depth: 2
 
 Introduction
 ============
 
-This chapter describes how to use the `FileIO API
+This section describes how to use the `FileIO API
 </native-client/pepper_stable/cpp/classpp_1_1_file_i_o>`_ to read and write
 files using a local secure data store.
 
 You might use the File IO API with the URL Loading APIs to create an overall
 data download and caching solution for your NaCl applications. For example:
 
 #. Use the File IO APIs to check the local disk to see if a file exists that
    your program needs.
 #. If the file exists locally, load it into memory using the File IO API. If
    the file doesn't exist locally, use the URL Loading API to retrieve the
    file from the server.
 #. Use the File IO API to write the file to disk.
 #. Load the file into memory using the File IO API when needed by your
    application.
 
-The example discussed in this chapter is included in the SDK in the directory
+The example discussed in this section is included in the SDK in the directory
 ``examples/api/file_io``.
 
 Reference information
 =====================
 
 For reference information related to FileIO, see the following documentation:
 
 * `file_io.h </native-client/pepper_stable/cpp/file__io_8h>`_ - API to create a
   FileIO object
 * `file_ref.h </native-client/pepper_stable/cpp/file__ref_8h>`_ - API to create
@@ skipping 502 matching lines @@
 
 .. naclcode::
 
   int32_t result = ref.MakeDirectory(
       PP_MAKEDIRECTORYFLAG_NONE, pp::BlockUntilComplete());
   if (result != PP_OK) {
     ShowErrorMessage("Make directory failed", result);
     return;
   }
   ShowStatusMessage("Make directory success");