Default the PacHttpsUrlStrippingEnabled policy to False for Chrome OS enterprise users.

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 8573 matching lines @@
       'name': 'PacHttpsUrlStrippingEnabled',
       'type': 'main',
       'schema': { 'type': 'boolean' },
       'supported_on': [ 'chrome.*:52-', 'chrome_os:52-' ],
       'features': {
         'dynamic_refresh': False,
         'per_profile': False,
       },
       'example_value': False,
       'id': 332,
+      'default_for_enterprise_users': False,
       'caption': '''Enable PAC URL stripping (for https://)''',
       'tags': ['system-security'],
       'desc': '''Strips privacy and security sensitive parts of https:// URLs before passing them on to PAC scripts (Proxy Auto Config) used by <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> during proxy resolution.
 
-      When not set (or set to true) the default behavior is to strip https:// URLs before submitting them to a PAC script. In this manner the PAC script is not able to view data that is ordinarily protected by an encrypted channel (like the path and query).
+      When True, the security feature is enabled, and https:// URLs are
+      stripped before submitting them to a PAC script. In this manner the PAC
+      script is not able to view data that is ordinarily protected by an
+      encrypted channel (such as the URL's path and query).
 
-      When the policy is set to false, this security feature is disabled, and PAC scripts are granted the ability to view the full URL. This setting applies to all PAC scripts regardless of origin. For instance it applies to PAC scripts obtained through WPAD as well as those fetched over an insecure transport.''',
+      When False, the security feature is disabled, and PAC scripts are
+      implicitly granted the ability to view all components of an https://
+      URL. This applies to all PAC scripts regardless of origin (including
+      those fetched over an insecure transport, or discovered insecurely
+      through WPAD).
+
+      This defaults to True (security feature enabled), except for Chrome OS
+      enterprise users for which this currently defaults to False.
+
+      It is recommended that this be set to True. The only reason to set it to
+      False is if it causes a compatibility problem with existing PAC scripts.
+
+      The desire is to remove this override in the future.''',

[Andrew T Wilson (Slow), 2016/06/07 12:59:02]

I believe this is reasonable as it stands, but ideally we'd put a concrete
release in there at some point.

     },
   ],
   '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''',
@@ skipping 110 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': [],
 }