Add a note about false positives on "copyright" word into licenses checker

android_webview/tools/webview_licenses.py

Index: android_webview/tools/webview_licenses.py
diff --git a/android_webview/tools/webview_licenses.py b/android_webview/tools/webview_licenses.py
index 6b87fc7d97eee1c1cfbe5a844809c190a5354703..ebd460957af2f60c12adba9b0527b4a90e324ad7 100755
--- a/android_webview/tools/webview_licenses.py
+++ b/android_webview/tools/webview_licenses.py
@@ -97,11 +97,14 @@ def _CheckLicenseHeaders(excluded_dirs_list, whitelisted_files):
   if unknown:
     print 'The following files contain a third-party license but are not in ' \
           'a listed third-party directory and are not whitelisted. You must ' \
-          'add the following files to the whitelist.\n%s' % \
+          'add the following files to the whitelist.\n' \
+          '(Note that if the code you are adding does not actually contain ' \
+          'any third-party code, it may contain the word "copyright", which ' \
+          'should be masked out, e.g. by writing it as "copy-right")\n%s' % \
           '\n'.join(sorted(unknown))
   if missing:
     print 'The following files are whitelisted, but do not exist.\n%s' % \
-        '\n'.join(sorted(missing))
+          '\n'.join(sorted(missing))
   if stale:
     print 'The following files are whitelisted unnecessarily. You must ' \
           'remove the following files from the whitelist.\n%s' % \