Adds a pref and a policy to decide if PDFs should always be opened externally.

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 119 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: 345
+#   For your editing convenience: highest ID currently used: 347
 #
 # 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
 #
 # Device Policy:
 #   An additional flag 'device_only' (optional, defaults to False) indicates
@@ skipping 1205 matching lines @@
       If you enable this setting, the specified list of plugins can be used in <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph>. Users can enable or disable them in 'about:plugins', even if the plugin also matches a pattern in DisabledPlugins. Users can also enable and disable plugins that don't match any patterns in DisabledPlugins, DisabledPluginsExceptions and EnabledPlugins.
 
       This policy is meant to allow for strict plugin blacklisting where the 'DisabledPlugins' list contains wildcarded entries like disable all plugins '*' or disable all Java plugins '*Java*' but the administrator wishes to enable some particular version like 'IcedTea Java 2.3'. This particular versions can be specified in this policy.
 
       Note that both the plugin name and the plugin's group name have to be exempted. Each plugin group is shown in a separate section in about:plugins; each section may have one or more plugins. For example, the "Shockwave Flash" plugin belongs to the "Adobe Flash Player" group, and both names have to have a match in the exceptions list if that plugin is to be exempted from the blacklist.
 
       If this policy is left not set any plugin that matches the patterns in the 'DisabledPlugins' will be locked disabled and the user won't be able to enable them.''',
       'label': '''List of exceptions to the list of disabled plugins''',
     },
     {
+      'name': 'AlwaysOpenPdfExternally',
+      'type': 'main',
+      'schema': { 'type': 'boolean' },
+      'supported_on': ['chrome.*:55-'],
+      'features': {
+        'dynamic_refresh': True,
+        'per_profile': True,
+      },
+      'example_value': True,
+      'id': 347,
+      'caption': '''Always Open PDF files externally''',
+      'tags': [],
+      'desc': '''Disables the internal PDF viewer in <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph>. Instead it treats it as download and allows the user to open PDF files with the default application.
+
+      If this policy is left not set or disabled the PDF plugin will be used to open PDF files unless the user disables it.''',
+    },
+    {
       'name': 'DisablePluginFinder',
       'type': 'main',
       'schema': { 'type': 'boolean' },
       'supported_on': ['chrome.*:11-', 'chrome_os:11-'],
       'features': {
         'dynamic_refresh': True,
         'per_profile': False,
       },
       'example_value': True,
       'id': 66,
@@ skipping 7734 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': [],
 }