Fix typo in 'adding_to_third_party.md' doc.

docs/adding_to_third_party.md

 # Adding third_party Libraries
 
 [TOC]
 
 Using third party code can save time and is consistent with our values - no need
 to reinvent the wheel! We put all code that isn't written by Chromium developers
 into src/third_party (even if you end up modifying just a few functions). We do
 this to make it easy to track license compliance, security patches, and supply
 the right credit and attributions. It also makes it a lot easier for other
 projects that embed our code to track what is Chromium licensed and what is
@@ skipping 47 matching lines @@
 ### Add a LICENSE file and run related checks
 
 You need a LICENSE file. Example:
 [third_party/libjpeg/LICENSE](http://src.chromium.org/viewvc/chrome/trunk/src/third_party/libjpeg/LICENSE?revision=42288&view=markup).
 
 Run the following scripts:
 
 * `src/tools/licenses.py scan` - This will complain about incomplete or missing
   data for third_party checkins. We use 'licenses.py credits' to generate the
   about:credits page in Google Chrome builds.
-* `src/tools/checklicenses/checklicenses.py` - See below for info how to handle
-  possible failures.
+* `src/tools/checklicenses/checklicenses.py` - See below for info on how to
+  handle possible failures.
 * If you are adding code that will be present in the content layer, please make
   sure that the license used is compliant with Android tree requirements because
   this code will also be used in Android WebView. You need to run
   `src/android_webview/tools/webview_licenses.py scan`
 
 See the ["Odds n' Ends"](adding_to_third_party.md#Odds-n_Ends) Section below if
 you run into any failures running these.
 
 If the library will never be shipped as a part of Chrome (e.g. build-time tools,
 testing tools), make sure to set "License File" as "NOT_SHIPPED" so that the
@@ skipping 113 matching lines @@
 
 * Missing license file
     * Make sure that the license file is present. It should be called 'LICENSE',
       or otherwise README.chromium file must point to it explicitly.
 * The following files contain a third-party license but are not in a listed
   third-party directory...
     * Check if it's a false positive (e.g. 'copyright' word used in a string
       literal), if so, update
       [src/tools/copyright_scanner/third_party_files_whitelist.txt](https://code.google.com/p/chromium/codesearch#chromium/src/tools/copyright_scanner/third_party_files_whitelist.txt)
       file. Otherwise, please move the code into third_party.