Adding a DownloadRestrictions group policy.

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 e572e88e4dbbe04bd4a915887cc09c3aee67e0f3..bb9eaa3ffc9dc64ea083bb19df52722bdf175e86 100644
--- a/components/policy/resources/policy_templates.json
+++ b/components/policy/resources/policy_templates.json
@@ -139,7 +139,7 @@
 #   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: 362
+#   For your editing convenience: highest ID currently used: 363
 #   And don't forget to also update the EnterprisePolicies enum of
 #   histograms.xml.
 #
@@ -296,7 +296,7 @@
           'name': 'NewTabPageLocation',
           'type': 'string',
           'schema': { 'type': 'string' },
-          'supported_on': ['chrome.*:57-', 'chrome_os:57-'],
+          'supported_on': ['chrome.*:58-', 'chrome_os:58-'],
           'features': {
             'can_be_recommended': True,
             'dynamic_refresh': True,
@@ -1689,6 +1689,50 @@
       'label': '''Set media disk cache size''',
     },
     {
+      'name': 'DownloadRestrictions',
+      'type': 'int-enum',
+      'schema': {
+        'type': 'integer',
+        'enum': [ 0, 1, 2, 3 ],
+      },
+      'items': [
+        {
+          'name': 'AllowDownloads',
+          'value': 0,
+          'caption': '''No restrictions''',
+        },
+        {
+          'name': 'DisableBlockedFiles',
+          'value': 1,
+          'caption': '''All downloads allowed, except for those that carry SafeBrowsing warnings.''',

[pastarmovj, 2017/02/06 07:45:00]

I know this CL is only a prototype still but I will put some comments here that
are more nits than actual issues.

The caption is too long and won't show well in the policy editor on windows. I
would go with a short cation e.g. "Allow all downloads" and then have a
paragraph about what each option does explained in the description below.

[MAD, 2017/02/06 19:41:33]

Done.

+        },
+        {
+          'name': 'DisableBlockedAndDangerousFiles',
+          'value': 2,
+          'caption': '''All downloads allowed, except for those that carry SafeBrowsing warnings or are of potentially dangerous filetypes.''',
+        },
+        {
+          'name': 'DisableDownloads',
+          'value': 3,
+          'caption': '''No downloads allowed, download functionality is disabled.''',
+        },
+      ],
+      'supported_on': ['chrome.*:58-', 'chrome_os:58-'],
+      'features': {
+        'can_be_recommended': True,
+        'dynamic_refresh': True,
+        'per_profile': True,
+      },
+      'example_value': 2,
+      'id': 363,
+      'caption': '''Allow download restrictions''',
+      'tags': ['local-data-access'],
+      'desc': '''Configures the type of downloads that <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will allow.
+
+      If you set this policy, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will prevent certain types of downloads.''',
+      'label': '''Allow download restrictions''',

[pastarmovj, 2017/02/06 07:45:00]

Download restrictions" might be a better name imho.

[MAD, 2017/02/06 19:41:33]

Done.

+    },
+    {
       'name': 'DownloadDirectory',
       'type': 'string',
       'schema': { 'type': 'string' },