Define Print Preview default printer selection 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 6b9d615f64f558614252b86ab7dd3ac761a3aa88..ebbed5b74fc2c2a9ebf3d85b3b5ae425c8468a63 100644
--- a/components/policy/resources/policy_templates.json
+++ b/components/policy/resources/policy_templates.json
@@ -123,7 +123,7 @@
 #   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: 307
+#   For your editing convenience: highest ID currently used: 308
 #
 # Placeholders:
 #   The following placeholder strings are automatically substituted:
@@ -4110,6 +4110,51 @@
       If this policy is not set or is set to false, print commands trigger the print preview screen.''',
     },
     {
+      'name': 'PrintPreviewDefaultPrinterSelection',
+      'type': 'string',
+      'schema': { 'type': 'string' },
+      'supported_on': ['chrome.*:48-', 'chrome_os:48-'],
+      'features': {
+        'dynamic_refresh': True,
+        'per_profile': True,
+      },
+      'example_value': '{ "kind": "cloud", "idPattern": ".*public", "namePattern": ".*Color" }',
+      'id': 308,
+      'caption': '''Default printer selection rules''',
+      'desc': '''Overrides <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> default printer selection rules.
+
+      This policy determines the rules for selecting the default printer in <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> which happens the first time the print function is used with a profile.
+
+      When this policy is set, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will attempt to find a printer matching the specified attributes, printer type, printer id and name pattern, and select it as default printer.

[Thiemo Nagel, 2015/10/12 19:10:09]

I think this would be clearer if the attributes weren't listed again, eg.:

"matching the specified attributes, printer type, printer id and name pattern,"
--> "matching all of the specified attributes"

BTW: What happens if the match is non-unique?  Which printer will be selected in
that case?  And what if there is no match?

[Aleksey Shlyapnikov, 2015/10/13 18:14:57]

Thank you for pointing that out, mentioned these cases too. Done.

+
+      If this policy is not set, the printer defaults to built-in PDF printer or no printer selected, when PDF printer is not available.
+
+      The value is parsed as JSON object, conforming to the following schema:
+      {
+        "type": "object",
+        "properties": {
+          "kind": {
+            "description": "Whether to limit the search of the matching printer to a specific set of printers.",
+            "type": {
+              "enum": [ "local", "cloud" ]
+            }
+          },
+          "idPattern": {
+            "description": "Regular expression to match printer id.",
+            "type": "string"
+          },
+          "namePattern": {
+            "description": "Regular expression to match printer display name.",
+            "type": "string"
+          }
+        }
+      }
+
+      Printers connected to Google Cloud Print are considered "cloud", the rest of the printers are classified as "local".
+      Omitting a field means all values match, for example, not specifying connectivity will cause Print Preview to initiate the discovery of all kinds of printers, local and cloud.
+      Regular expression patterns are case sensistive.''',
+    },
+    {
       'name': 'DisableSSLRecordSplitting',
       'type': 'main',
       'schema': { 'type': 'boolean' },