Add PolicyData to distinguish EDU from Enterprise users for metrics

We will create a new PolicyData field to distinguish K-12 EDU from
Enterprise accounts in ChromeOS for the initial version of metrics.
This flag should only be used for metrics as the Enterprise team does
not want any differential treatment of EDU and Enterprise users in
ChromeOS beyond this particular use case. This method of
distinguishing EDU and Enterprise accounts only works for the primary
account, as user policy doesn't apply for secondary accounts.

Bug: 1103077
Change-Id: I1f27cd1b0b4ffe62bcb85459e070627dfdd509fd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2292703Reviewed-by: Aga Wronska <agawronska@chromium.org>
Reviewed-by: Bartosz Fabianowski <bartfab@chromium.org>
Commit-Queue: Toby Huang <tobyhuang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789163}

components/policy/proto/device_management_backend.proto

@@ -670,6 +670,19 @@ message PolicyData {
   // Obfuscated customerId the device is enrolled into.
   // Only set for device policy.
   optional string obfuscated_customer_id = 34;
+
+  // The different types of user segments for metrics logging.
+  enum MetricsLogSegment {
+    UNSPECIFIED = 0;
+    K12 = 1;
+    UNIVERSITY = 2;
+    NONPROFIT = 3;
+  }
+
+  // Indicates the segment the user's metrics should be logged under,
+  // UNSPECIFIED if not relevant.
+  // This field should only be set for User Policy response.
+  optional MetricsLogSegment metrics_log_segment = 35;
 }
 
 message ClientActionRequired {