Add policy to control valid UDP port range in WebRTC

components/policy/resources/policy_templates.json

Index: components/policy/resources/policy_templates.json
diff --git a/components/policy/resources/policy_templates.json b/components/policy/resources/policy_templates.json
index 2751effe1c548bb95912cd0ea499cce7a11effa6..4fca508aac93ff69fee3c5c81c76f1a33a6132e5 100644
--- a/components/policy/resources/policy_templates.json
+++ b/components/policy/resources/policy_templates.json
@@ -137,7 +137,7 @@
 #   persistent IDs for all fields (but not for groups!) are needed. These are
 #   specified by the 'id' keys of each policy. NEVER CHANGE EXISTING IDs,
 #   because doing so would break the deployed wire format!
-#   For your editing convenience: highest ID currently used: 338
+#   For your editing convenience: highest ID currently used: 339
 #
 # Placeholders:
 #   The following placeholder strings are automatically substituted:
@@ -8795,6 +8795,23 @@
 
       If this is set to false, automatically-generated content suggestions are not shown on the New Tab page.''',
     },
+    {
+      'name': 'WebRtcUdpPortRange',
+      'type': 'string',
+      'schema': { 'type': 'string' },
+      'supported_on': ['chrome.*:54-', 'chrome_os:54-'],
+      'features': {
+        'dynamic_refresh': False,
+        'per_profile': True,
+      },
+      'example_value': '10000-11999',
+      'id': 339,
+      'caption': '''Restrict the UDP port range used by WebRTC''',
+      'tags': [],
+      'desc': '''Restricts the UDP port range used by WebRTC in this machine.

[Thiemo Nagel, 2016/08/11 09:29:26]

Nit: I'm not in favour of duplicating the caption in the description (although
there is ample precedent for it).

[Guido Urdaneta, 2016/08/11 10:10:25]

Done.

[Thiemo Nagel, 2016/08/11 10:22:31]

As a second thought, I think it would be better spell out what the policy does a
bit more explicitly, eg.: "If the policy is set, the UDP port range used by
WebRTC is restricted to the specified port interval (endpoints included)."

[Guido Urdaneta, 2016/08/11 10:31:19]

Done.

+
+      If this policy is left not set, or if it is set to an empty string or an invalid port range, WebRTC will be allowed to use any available port.''',

[Thiemo Nagel, 2016/08/11 09:29:26]

Nit: In my opinion present tense is better style.

[Guido Urdaneta, 2016/08/11 10:10:25]

Done.

[Thiemo Nagel, 2016/08/11 10:22:32]

Optional nit: Actually it's still future tense. ;)

[Guido Urdaneta, 2016/08/11 10:31:19]

Done. I originally thought you meant you didn't like passive voice :)

+    },
   ],
   'messages': {
     # Messages that are not associated to any policies.