Add a policy to always show the Cast toolbar icon

components/policy/resources/policy_templates.json

 {
 # policy_templates.json - Metafile for policy templates
 #
 # The content of this file is evaluated as a Python expression.
 #
 # This file is used as input to generate the following policy templates:
 # ADM, ADMX+ADML, MCX/plist and html documentation.
 #
 # Policy templates are user interface definitions or documents about the
 # policies that can be used to configure Chrome. Each policy is a name-value
@@ skipping 121 matching lines @@
 #   templates and documentation. The policy definition list that Chrome sees
 #   will include policies marked with 'future'. If a WIP policy isn't meant to
 #   be seen by the policy providers either, the 'supported_on' key should be set
 #   to an empty list.
 #
 # IDs:
 #   Since a Protocol Buffer definition is generated from this file, unique and
 #   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: 360
+#   For your editing convenience: highest ID currently used: 361
 #   And don't forget to also update the EnterprisePolicies enum of
 #   histograms.xml.
 #
 # Placeholders:
 #   The following placeholder strings are automatically substituted:
 #     $1 -> Google Chrome / Chromium
 #     $2 -> Google Chrome OS / Chromium OS
 #     $3 -> Google Chrome Frame / Chromium Frame
 #     $6 is reserved for doc_writer
 #
@@ skipping 8953 matching lines @@
       'schema': { 'type': 'boolean' },
       'supported_on': ['chrome.*:52-', 'chrome_os:52-', 'android:52-'],
       'features': {
         'dynamic_refresh': False,
         'per_profile': True,
       },
       'example_value': True,
       'id': 333,
       'caption': '''Enables cast''',
       'tags': [],
       'desc': '''If this is set to true or is not set, users will be able to cast tabs, sites or the desktop from the browser. If set to false, this option will be disabled.'''

[pastarmovj, 2017/01/24 23:03:46]

Please rework the description of this policy. This text is shown in the Group
policy Editor and therefore is considered public Chrome documentation. See the
policy below for inspiration.

Don't forget to include the section what happens if this policy is not set at
all. This is MS recommendation about the format.

Also what is "cast" in the label? Is this the "Chrome Cast" thing or is this
some generic name for a standard/protocol?

PS. Sorry to hi-jack the new policy to ask for these changes but I feel this
documentation has not been thoroughly reviewed when it was added in the first
place.

[takumif, 2017/01/26 23:12:35]

Replacing 'cast' with 'Google Cast' and putting a description for it. The case
for the policy not being set is covered in the first sentence.

Sorry, what do you mean by MS recommendation?

[pastarmovj, 2017/01/26 23:18:13]

I meant the Microsoft guidelines for documenting policies. I can't dig the link
now but basically it says one should document the default behavior when the
policy is not set. 

I am sorry I missed the "...or is not set". It's good like it is.

     },
     {
       'name': 'ArcBackupRestoreEnabled',
       'type': 'main',
       'schema': { 'type': 'boolean' },
       'supported_on': ['chrome_os:53-'],
       'features': {
         'dynamic_refresh': True,
         'per_profile': False,
       },
@@ skipping 315 matching lines @@
       The policy should be speicified as a string that expresses the URL and hash in JSON format, e.g.,
       {
         "url": "https://example.com/device_wallpaper.jpg",
         "hash": "examplewallpaperhash"
       }
 
       If the device wallpaper policy is set, the Chrome OS device will download and use the wallpaper image on the login screen if no user has yet signed in to the device. Once the user logs in, the user's wallpaper policy kicks in.
 
       If the device wallpaper policy is left not set, it's the user's wallpaper policy to decide what to show if the user's wallpaper policy is set.''',
     },
+    {
+      'name': 'ShowCastIconInToolbar',

[pastarmovj, 2017/01/24 23:03:46]

Please move this policy right after the EnableMediaRouter policy and consider
grouping them in a group called "Chrome Cast" or some such.

[takumif, 2017/01/26 23:12:35]

Putting them in a group 'Google Cast'.

+      'type': 'main',
+      'schema': { 'type': 'boolean' },
+      'supported_on': ['chrome.*:57-', 'chrome_os:57-'],
+      'features': {
+        'dynamic_refresh': False,
+        'per_profile': True,
+      },
+      'example_value': False,
+      'id': 361,
+      'caption': '''Shows the Cast toolbar icon''',
+      'tags': [],
+      'desc': '''If this policy is set to true, the Cast toolbar icon will always be shown on the toolbar or the overflow menu, and users will not be able to remove it.
+
+      If this policy is set to false or not set, users will be able to pin or remove the icon via its contextual menu.
+
+      If the policy "EnableMediaRouter" is set to false, then this policy's value would have no effect, and the toolbar icon would not be shown.'''
+    },
   ],
   'messages': {
     # Messages that are not associated to any policies.
     'win_supported_winxpsp2': {
       'desc': '''A label specifying the oldest possible compatible version of Windows. This text will appear right next to a label containing the text 'Supported on:'.''',
       'text': '''Microsoft Windows XP SP2 or later'''
     },
     'mac_chrome_preferences': {
       'desc': '''A text indicating in Mac OS X Workgroup Manager, that currently the preferences of Chromium are being edited''',
       'text': '''<ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> preferences'''
@@ skipping 113 matching lines @@
       'desc': '''Text appended in parentheses next to the policies top-level container to indicate that those policies are of the Recommended level''',
       'text': 'Default Settings (users can override)',
     },
     'doc_complex_policies_on_windows': {
       'desc': '''Text pointing the user to a help article for complex policies on Windows''',
       'text': '''encoded as a JSON string, for details see <ph name="COMPLEX_POLICIES_URL">https://www.chromium.org/administrators/complex-policies-on-windows<ex>https://www.chromium.org/administrators/complex-policies-on-windows</ex></ph>''',
     },
   },
   'placeholders': [],
 }