Implement policy for kNetworkPredictionOptions.

chrome/test/data/policy/policy_test_cases.json

 {
   "-- Template --": {
     "intro": "Top-level entries map a policy name to its test parameters, described below. The name of the top level entry should be of the form <policy name>[.suffix]. The optional suffix is used for defining multiple test cases for a single policy.",
 
     "os": ["List of operating systems that support this policy. Valid values:", "win", "linux", "mac", "chromeos", "Defaults to empty if not specified."],
     "official_only": "Whether this policy exists in official builds only. Defaults to |false| if not specified.",
     "can_be_recommended": "Whether a recommended value may be set for the policy. Defaults to |false| if not specified.",
     "test_policy": "A policy dictionary that should make the preferences affected by this policy become policy-controlled. Usually just sets the current policy. Defaults to an empty dictionary if not specified.",
     "note": "If the policy affects any preferences, the following array should be specified with one entry per such preference.",
     "pref_mappings": [
@@ skipping 103 matching lines @@
     "test_policy": { "DnsPrefetchingEnabled": false },
     "pref_mappings": [
       { "pref": "dns_prefetching.enabled",
         "indicator_tests": [
           { "policy": { "DnsPrefetchingEnabled": false } }
         ]
       }
     ]
   },
 
+  "NetworkPredictionOptions": {
+    "os": ["win", "linux", "mac", "chromeos"],
+    "can_be_recommended": true,
+    "test_policy": { "NetworkPredictionOptions": 2 },
+    "pref_mappings": [
+      { "pref": "net.network_prediction_options",

[Joao da Silva, 2014/07/30 13:33:32]

Setting this value to the old value should fix the test
("dns_prefetching.enabled").

This will test that setting the "NetworkPredictionOptions" policy shows an icon
in the settings indicating that "this is managed by your administrator" (you can
see a lot of managed settings in your browser if you use Chrome in a corp
workstation).

However, the option to "Use a prediction service to help complete searches etc
etc" option is still mapped to "dns_prefetching.enabled". The test fails because
it's trying to locate the management warning icon next to a control that maps to
this new pref, but none exists.

Setting this "pref" to the old one is the right fix because that's still what
the settings UI is using. Once you update that (see
chrome/browser/resources/options/browser_options.html) then this "pref" here
should be updated too.

[Bence, 2014/07/31 20:41:11]

Done.

+        "indicator_tests": [
+          { "policy": { "NetworkPredictionOptions": 2 } }
+        ]
+      }
+    ]
+  },
+
   "DisableSpdy": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "DisableSpdy": true },
     "pref_mappings": [
       { "pref": "spdy.disabled" }
     ]
   },
 
   "DisabledSchemes": {
     "os": ["win", "linux", "mac", "chromeos"],
@@ skipping 2199 matching lines @@
 
   "AdditionalLaunchParameters": {
   },
 
   "SuppressChromeFrameTurndownPrompt": {
   },
 
   "SkipMetadataCheck": {
   }
 }