Pack policy::PolicyDetails slightly more.

A cheap way of saving a kilobyte of binary size by simply making some
fields narrower. This decreases the size of this from 20 bytes to
12 bytes per entry. 8 bytes could be done with some more intrusive
repacking, but there are diminishing returns.

Change-Id: If89d2025b6b374766d602cd7caafac5e675d4c7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2243252
Commit-Queue: Owen Min <zmin@chromium.org>
Auto-Submit: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805383}

components/policy/core/common/policy_details.h

@@ -18,13 +18,13 @@ namespace policy {
 // Contains read-only metadata about a Chrome policy.
 struct POLICY_EXPORT PolicyDetails {
   // True if this policy has been deprecated.
-  bool is_deprecated;
+  bool is_deprecated : 1;
 
   // True if the policy hasn't been released yet.
-  bool is_future;
+  bool is_future : 1;
 
   // True if this policy is a Chrome OS device policy.
-  bool is_device_policy;
+  bool is_device_policy : 1;
 
   // The id of the protobuf field that contains this policy,
   // in the cloud policy protobuf.

components/policy/tools/generate_policy_source.py

@@ -1283,7 +1283,7 @@ class RiskTags(object):
     values = ['  ' + self.enum_for_tag[tag] for tag in self.enum_for_tag]
     values.append('  RISK_TAG_COUNT')
     values.append('  RISK_TAG_NONE')
-    enum_text = 'enum RiskTag {\n'
+    enum_text = 'enum RiskTag : uint8_t {\n'
     enum_text += ',\n'.join(values) + '\n};\n'
     return enum_text