Convert TrackedPreferenceValidationDelegate into a mojo interface.

services/preferences/public/interfaces/tracked_preference_validation_delegate.mojom

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module prefs.mojom;
+
+import "mojo/common/values.mojom";
+
+// A TrackedPreferenceValidationDelegate is notified of the results of each
+// tracked preference validation event.
+interface TrackedPreferenceValidationDelegate {
+  enum ValueState {
+    // The preference value corresponds to its stored hash.
+    UNCHANGED,
+    // The preference has been cleared since the last hash.
+    CLEARED,
+    // The preference value corresponds to its stored hash, but the hash was
+    // calculated using a deprecated hash algorithm which is just as safe as
+    // the current one.
+    SECURE_LEGACY,
+    // The preference value has been changed since the last hash.
+    CHANGED,
+    // No stored hash exists for the preference value.
+    UNTRUSTED_UNKNOWN_VALUE,
+    // No stored hash exists for the preference value, but the current set of
+    // hashes stored is trusted and thus this value can safely be seeded. This
+    // happens when all hashes are already properly seeded and a newly
+    // tracked value needs to be seeded).
+    TRUSTED_UNKNOWN_VALUE,
+    // Null values are inherently trusted.
+    TRUSTED_NULL_VALUE,
+    // This transaction's store type is not supported.
+    UNSUPPORTED,
+  };
+
+  // Notifies observes of the result (|value_state|) of checking the atomic
+  // |value| (which may be null) at |pref_path|. |is_personal| indicates whether
+  // or not the value may contain personal information.
+  OnAtomicPreferenceValidation(
+      string pref_path,
+      mojo.common.mojom.Value? value,
+      ValueState value_state,
+      ValueState external_validation_value_state,
+      bool is_personal);
+
+  // Notifies observes of the result (|value_state|) of checking the split
+  // value at |pref_path|. |is_personal| indicates whether or not the value may
+  // contain personal information.
+  OnSplitPreferenceValidation(
+      string pref_path,
+      array<string> invalid_keys,
+      array<string> external_validation_invalid_keys,
+      ValueState value_state,
+      ValueState external_validation_value_state,
+      bool is_personal);
+};