Correct some details in the instructions for modifying TTS engine.

docs/accessibility/patts.md

 # The Chrome OS PATTS speech synthesis engine
 
 Chrome OS comes with a speech synthesis engine developed internally at Google
 called PATTS. It's based on the same engine that ships with all Android devices.
 
 ## Building from source
 
 This is for Googlers only.
 
 Visit [http://go/chrome-tts-blaze](http://go/chrome-tts-blaze)
@@ skipping 15 matching lines @@
 you can do this with the following command when the dev server is running,
 where CHROMEBOOK_IP_ADDRESS is the IP address of your Chromebook already
 in developer mode, and $BOARD is your Chromebook's board name.
 
 ```cros flash ssh://CHROMEBOOK_IP_ADDRESS xbuddy://remote/$BOARD/latest-dev/test```
 
 Before you can make changes to PATTS, the first thing you need to run
 (from the chroot) is call cros_workon with two relevant ebuilds:
 
 ```
-cros_workon --board=$BOARD start chromeos-assets
+cros_workon --board=$BOARD start chromiumos-assets

[dmazzoni, 2017/02/25 01:56:18]

Is it possible the difference has to do with whether you have the
internal or external sources checked out? Or did this change recently
maybe?

I'm not disputing this worked for you, I'm just trying to better
understand it...

[Wez, 2017/02/25 02:06:52]

That's a good question; I did indeed just follow the public instructions, so
quite possibly.

 cros_workon --board=$BOARD start common-assets
 ```
 
-Next, make sure you're in the platform/assets directory and run
-```repo start``` and create a branch.
+From outside the root, from anywhere under your top-level ```<repo-dir>```, pull down the relevant sources:
 
 ```
-cd platform/assets
+repo sync
+```
+
+Again, outside the root, make sure you're in the ```<repo-dir>/src/platform/assets``` directory and run
+```repo start``` to create a branch:
+
+```
+cd src/platform/assets
 repo start <branch_name> .
 ```
 
 
 The PATTS data files can be found in this directory:
 
-```platform/assets/speech_synthesis/patts```
+```src/platform/assets/speech_synthesis/patts```
 
 When updating the files, the native client files (nexe) need to be zipped.
 
 Replace all of the files you need to update, commit them using git,
 then from the chroot, run:
 
 ```
 emerge-$BOARD common-assets
 cros deploy CHROMEBOOK_IP_ADDRESS common-assets
 ```
 
 Note that you need to call cros_workon on both chromeos-assets and
 common-assets. You will be changing files in chromeos-assets, but
 to flash it onto your device, you need to emerge and deploy
 common-assets.
 
 After that, reboot your Chromebook and verify that speech works.
 
 To upload the change, use repo upload, something like this:
 
 ```
 git commit -a
   BUG=chromium:12345
   TEST=Write what you tested here
 repo upload .
 ```