Add a script to test Chrome with the NVDA screen reader.

tools/accessibility/nvda/README.txt

+This directory contains semi-automated tests of Chrome with
+NVDA (NonVisual Desktop Access), a popular open-source screen reader for
+visually impaired users on Windows. It works by launching Chrome in a
+subprocess, then launching NVDA in a special environment that simulates
+speech rather than actually speaking, and ignores all events coming from
+processes other than a specific Chrome process ID. Each test automates
+Chrome with a series of actions and asserts that NVDA gives the expected
+feedback in response.
+
+Instructions for running these tests:
+
+1. Install Python 2.7, 32-bit: http://www.python.org/
+
+   Note - the version of Python installed by Chrome's depot_tools will not
+   work, it's 64-bit.
+
+2. Download pywinauto here:
+     https://code.google.com/p/pywinauto/downloads/list
+
+   Unzip it, then install it by running this from a cmd shell in that directory:
+     python setup.py install
+
+   If you get an error, make sure you're using the 32-bit version of Python.
+
+3. Install the latest NVDA "next" snapshot from:
+   http://community.nvda-project.org/wiki/Snapshots
+
+   In the installer, choose "Create Portable copy" rather than "Install...".
+   From the Browse dialog, create an new folder called nvdaPortable inside
+   this folder.
+
+   Note: after NVDA 2014.3 stable is released, just use the stable version
+   instead, from http://www.nvaccess.org/download/
+   - if you do this, you need to run NVDA, then from the NVDA menu, choose
+   Tools > Create Portable Copy.
+   From the Browse dialog, create an new folder called nvdaPortable inside
+   this folder.
+   You should now have something like this:
+     d:\src\nvda_chrome_tests\nvdaPortable\nvda.exe
+   You can now exit NVDA.
+
+4. Install Chrome Canary. The binary is typically installed in:
+   c:\Users\USERNAME\AppData\Local\Google\Chrome SxS\Application\chrome.exe
+   ...if not, edit nvda_chrome_tests.py to point to it.
+
+5. Clone the nvda-proctest environment into this directory:
+   git clone https://bitbucket.org/nvaccess/nvda-proctest.git
+
+6. Run the tests:
+
+   First make sure NVDA is not already running.
+
+   Open a cmd console, change to the nvda_chrome_tests directory, and run:
+   python nvda_chrome_tests.py
+
+   If you get an error, open the Windows task manager and make sure NVDA
+   isn't running, kill it if necessary.
+