Add a policy list for access to capture devices

chrome/test/data/policy/policy_test_cases.json

 {
   "-- Template --": {
     "intro": "Top-level entries map a policy name to its test parameters, described below.",
 
     "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 946 matching lines @@
     "pref_mappings": [
       { "pref": "hardware.audio_capture_enabled",
         "indicator_selector": "#media-indicator",
         "indicator_tests": [
           { "policy": { "AudioCaptureAllowed": false } }
         ]
       }
     ]
   },
 
+  "AudioCaptureAllowedUrls": {
+  },
+
   "VideoCaptureAllowed": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "VideoCaptureAllowed": false },
     "pref_mappings": [
       { "pref": "hardware.video_capture_enabled",
         "indicator_selector": "#media-indicator",
         "indicator_tests": [
           { "policy": { "VideoCaptureAllowed": false } }
         ]
       }
     ]
   },
 
+  "VideoCaptureAllowedUrls": {
+  },
+
   "AutoSelectCertificateForUrls": {
     "os": ["win", "linux", "mac", "chromeos"],
     "test_policy": { "AutoSelectCertificateForUrls": ["{'pattern':'https://example.com','filter':{'ISSUER':{'CN': 'issuer-name'}}}"] },
     "pref_mappings": [
       { "pref": "profile.managed_auto_select_certificate_for_urls" }
     ],
 
     "note": "TODO(bartfab): Flag this with can_be_recommended when http://crbug.com/106682 is fixed."
   },
 
@@ skipping 910 matching lines @@
 
   "ChromeFrameContentTypes": {
   },
 
   "GCFUserDataDir": {
   },
 
   "AdditionalLaunchParameters": {
   }
 }