Add default enum value to ChannelDowngradeBehavior

Add a default value to the device policy enum for
ChannelDowngradeBehavior.

Bug: 1110808
Change-Id: Id5caf1988c0f2c4b9699a058213c772567316811
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2345145
Commit-Queue: Alexander Hendrich <hendrich@chromium.org>
Auto-Submit: Miriam Polzer <mpolzer@google.com>
Reviewed-by: Jit Yao Yap <jityao@google.com>
Reviewed-by: Alexander Hendrich <hendrich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796326}

components/policy/proto/chrome_device_policy.proto

@@ -320,16 +320,19 @@ message AutoUpdateSettingsProto {
 
   // Types of channel downgrade behavior.
   enum ChannelDowngradeBehavior {
+    // Channel downgrade behavior unspecified. Default is
+    // WAIT_FOR_VERSION_CATCH_UP.
+    CHANNEL_DOWNGRADE_BEHAVIOR_UNSPECIFIED = 0;
     // On a channel downgrade, e.g. beta to stable, wait for the device's
     // version to become available on the new channel. No updates happen until
     // then. This is the default.
-    WAIT_FOR_VERSION_CATCH_UP = 0;
+    WAIT_FOR_VERSION_CATCH_UP = 1;
     // Roll back and reset the device on a channel downgrade. This does a full
     // powerwash and tries to preserve wifi and enrollment.
-    ROLLBACK = 1;
+    ROLLBACK = 2;
     // Allow the user to decide whether to wait or roll back and reset on a
     // user-initiated channel downgrade.
-    ALLOW_USER_TO_CONFIGURE = 2;
+    ALLOW_USER_TO_CONFIGURE = 3;
   }
 
   // Specifies what should happen if the device channel is downgraded.

components/policy/resources/policy_templates.json

@@ -9353,22 +9353,22 @@
       'type': 'int-enum',
       'schema': {
         'type': 'integer',
-        'enum': [0, 1, 2],
+        'enum': [1, 2, 3],
       },
       'items': [
         {
           'name': 'WaitForVersionCatchUp',
-          'value': 0,
+          'value': 1,
           'caption': '''Wait for the target channel to catch up on channel downgrade''',
         },
         {
           'name': 'Rollback',
-          'value': 1,
+          'value': 2,
           'caption': '''Roll back and reset the device on channel downgrade, try to preserve enrollment''',
         },
         {
           'name': 'AllowUserToConfigure',
-          'value': 2,
+          'value': 3,
           'caption': '''User decides on channel downgrade behavior''',
         },
       ],
@@ -9377,7 +9377,7 @@
       'features': {
         'dynamic_refresh': True,
       },
-      'example_value': 0,
+      'example_value': 1,
       'id': 757,
       'caption': '''Channel downgrade behavior''',
       'tags': [],