diff --git a/buffet/commands/unittest_utils.h b/buffet/commands/unittest_utils.h
index 665a2d1..577405a 100644
--- a/buffet/commands/unittest_utils.h
+++ b/buffet/commands/unittest_utils.h
@@ -10,6 +10,9 @@
 
 #include <base/values.h>
 
+#include "buffet/commands/prop_types.h"
+#include "buffet/commands/prop_values.h"
+
 namespace buffet {
 namespace unittests {
 
@@ -25,6 +28,34 @@
 // apostrophes for easy comparisons in C++ source code.
 std::string ValueToString(const base::Value* value);
 
+template <typename PV, typename T> std::shared_ptr<const PV>
+make_prop_value(const PropType* type, const T& value) {
+  auto result = std::make_shared<PV>(type);
+  result->SetValue(value);
+  return result;
+}
+
+inline std::shared_ptr<const IntValue> make_int_prop_value(int value) {
+  static const PropType* int_prop_type = new IntPropType();
+  return make_prop_value<IntValue, int>(int_prop_type, value);
+}
+
+inline std::shared_ptr<const DoubleValue> make_double_prop_value(double value) {
+  static const PropType* double_prop_type = new DoublePropType();
+  return make_prop_value<DoubleValue, double>(double_prop_type, value);
+}
+
+inline std::shared_ptr<const BooleanValue> make_bool_prop_value(bool value) {
+  static const PropType* boolean_prop_type = new BooleanPropType();
+  return make_prop_value<BooleanValue, bool>(boolean_prop_type, value);
+}
+
+inline std::shared_ptr<const StringValue>
+make_string_prop_value(const std::string& value) {
+  static const PropType* string_prop_type = new StringPropType();
+  return make_prop_value<StringValue, std::string>(string_prop_type, value);
+}
+
 }  // namespace unittests
 }  // namespace buffet
 
diff --git a/buffet/states/mock_state_change_queue_interface.h b/buffet/states/mock_state_change_queue_interface.h
index 11a84b4..54b2ccc 100644
--- a/buffet/states/mock_state_change_queue_interface.h
+++ b/buffet/states/mock_state_change_queue_interface.h
@@ -18,7 +18,7 @@
   MOCK_CONST_METHOD0(IsEmpty, bool());
   MOCK_METHOD2(NotifyPropertiesUpdated,
                bool(base::Time timestamp,
-                    chromeos::VariantDictionary changed_properties));
+                    native_types::Object changed_properties));
   MOCK_METHOD0(GetAndClearRecordedStateChanges, std::vector<StateChange>());
 };
 
diff --git a/buffet/states/state_change_queue.cc b/buffet/states/state_change_queue.cc
index f27b339..74ac682 100644
--- a/buffet/states/state_change_queue.cc
+++ b/buffet/states/state_change_queue.cc
@@ -15,7 +15,7 @@
 
 bool StateChangeQueue::NotifyPropertiesUpdated(
     base::Time timestamp,
-    chromeos::VariantDictionary changed_properties) {
+    native_types::Object changed_properties) {
   DCHECK(thread_checker_.CalledOnValidThread());
   auto it = state_changes_.lower_bound(timestamp);
   if (it == state_changes_.end() || it->first != timestamp) {
diff --git a/buffet/states/state_change_queue.h b/buffet/states/state_change_queue.h
index 2ca46e6..9181ef4 100644
--- a/buffet/states/state_change_queue.h
+++ b/buffet/states/state_change_queue.h
@@ -24,7 +24,7 @@
   bool IsEmpty() const override { return state_changes_.empty(); }
   bool NotifyPropertiesUpdated(
       base::Time timestamp,
-      chromeos::VariantDictionary changed_properties) override;
+      native_types::Object changed_properties) override;
   std::vector<StateChange> GetAndClearRecordedStateChanges() override;
 
  private:
@@ -38,7 +38,7 @@
   const size_t max_queue_size_;
 
   // Accumulated list of device state change notifications.
-  std::map<base::Time, chromeos::VariantDictionary> state_changes_;
+  std::map<base::Time, native_types::Object> state_changes_;
 
   DISALLOW_COPY_AND_ASSIGN(StateChangeQueue);
 };
diff --git a/buffet/states/state_change_queue_interface.h b/buffet/states/state_change_queue_interface.h
index 84704dd..0532788 100644
--- a/buffet/states/state_change_queue_interface.h
+++ b/buffet/states/state_change_queue_interface.h
@@ -10,6 +10,8 @@
 #include <base/time/time.h>
 #include <chromeos/variant_dictionary.h>
 
+#include "commands/schema_utils.h"
+
 namespace buffet {
 
 // A simple notification record event to track device state changes.
@@ -18,10 +20,10 @@
 // which were updated at the time the event was recorded.
 struct StateChange {
   StateChange(base::Time time,
-              chromeos::VariantDictionary properties)
+              native_types::Object properties)
     : timestamp(time), changed_properties(std::move(properties)) {}
   base::Time timestamp;
-  chromeos::VariantDictionary changed_properties;
+  native_types::Object changed_properties;
 };
 
 // An abstract interface to StateChangeQueue to record and retrieve state
@@ -34,7 +36,7 @@
   // Called by StateManager when device state properties are updated.
   virtual bool NotifyPropertiesUpdated(
       base::Time timestamp,
-      chromeos::VariantDictionary changed_properties) = 0;
+      native_types::Object changed_properties) = 0;
 
   // Returns the recorded state changes since last time this method was called.
   virtual std::vector<StateChange> GetAndClearRecordedStateChanges() = 0;
diff --git a/buffet/states/state_change_queue_unittest.cc b/buffet/states/state_change_queue_unittest.cc
index 01f5f9f..68fadcc 100644
--- a/buffet/states/state_change_queue_unittest.cc
+++ b/buffet/states/state_change_queue_unittest.cc
@@ -7,6 +7,8 @@
 
 #include <gtest/gtest.h>
 
+#include "buffet/commands/unittest_utils.h"
+
 namespace buffet {
 
 class StateChangeQueueTest : public ::testing::Test {
@@ -30,7 +32,7 @@
 TEST_F(StateChangeQueueTest, UpdateOne) {
   StateChange change{
     base::Time::Now(),
-    chromeos::VariantDictionary{{"prop.name", int{23}}}
+    native_types::Object{{"prop.name", unittests::make_int_prop_value(23)}}
   };
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(change.timestamp,
                                               change.changed_properties));
@@ -46,16 +48,16 @@
 TEST_F(StateChangeQueueTest, UpdateMany) {
   StateChange change1{
     base::Time::Now(),
-    chromeos::VariantDictionary{{"prop.name1", int{23}}}
+    native_types::Object{{"prop.name1", unittests::make_int_prop_value(23)}}
   };
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(change1.timestamp,
                                               change1.changed_properties));
   StateChange change2{
     base::Time::Now(),
-    chromeos::VariantDictionary{
-      {"prop.name1", int{17}},
-      {"prop.name2", double{1.0}},
-      {"prop.name3", bool{false}},
+    native_types::Object{
+      {"prop.name1", unittests::make_int_prop_value(17)},
+      {"prop.name2", unittests::make_double_prop_value(1.0)},
+      {"prop.name3", unittests::make_bool_prop_value(false)},
     }
   };
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(change2.timestamp,
@@ -77,29 +79,29 @@
 
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(
       timestamp,
-      chromeos::VariantDictionary{{"prop.name1", int{1}}}));
+      native_types::Object{{"prop.name1", unittests::make_int_prop_value(1)}}));
 
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(
       timestamp,
-      chromeos::VariantDictionary{{"prop.name2", int{2}}}));
+      native_types::Object{{"prop.name2", unittests::make_int_prop_value(2)}}));
 
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(
       timestamp,
-      chromeos::VariantDictionary{{"prop.name1", int{3}}}));
+      native_types::Object{{"prop.name1", unittests::make_int_prop_value(3)}}));
 
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(
       timestamp + time_delta,
-      chromeos::VariantDictionary{{"prop.name1", int{4}}}));
+      native_types::Object{{"prop.name1", unittests::make_int_prop_value(4)}}));
 
   auto changes = queue_->GetAndClearRecordedStateChanges();
   ASSERT_EQ(2, changes.size());
 
-  chromeos::VariantDictionary expected1{
-    {"prop.name1", int{3}},
-    {"prop.name2", int{2}},
+  native_types::Object expected1{
+    {"prop.name1", unittests::make_int_prop_value(3)},
+    {"prop.name2", unittests::make_int_prop_value(2)},
   };
-  chromeos::VariantDictionary expected2{
-    {"prop.name1", int{4}},
+  native_types::Object expected2{
+    {"prop.name1", unittests::make_int_prop_value(4)},
   };
   EXPECT_EQ(timestamp, changes[0].timestamp);
   EXPECT_EQ(expected1, changes[0].changed_properties);
@@ -115,39 +117,39 @@
 
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(
       start_time,
-      chromeos::VariantDictionary{
-        {"prop.name1", int{1}},
-        {"prop.name2", int{2}},
+      native_types::Object{
+        {"prop.name1", unittests::make_int_prop_value(1)},
+        {"prop.name2", unittests::make_int_prop_value(2)},
       }));
 
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(
       start_time + time_delta1,
-      chromeos::VariantDictionary{
-        {"prop.name1", int{3}},
-        {"prop.name3", int{4}},
+      native_types::Object{
+        {"prop.name1", unittests::make_int_prop_value(3)},
+        {"prop.name3", unittests::make_int_prop_value(4)},
       }));
 
   ASSERT_TRUE(queue_->NotifyPropertiesUpdated(
       start_time + time_delta2,
-      chromeos::VariantDictionary{
-        {"prop.name10", int{10}},
-        {"prop.name11", int{11}},
+      native_types::Object{
+        {"prop.name10", unittests::make_int_prop_value(10)},
+        {"prop.name11", unittests::make_int_prop_value(11)},
       }));
 
   auto changes = queue_->GetAndClearRecordedStateChanges();
   ASSERT_EQ(2, changes.size());
 
-  chromeos::VariantDictionary expected1{
-    {"prop.name1", int{3}},
-    {"prop.name2", int{2}},
-    {"prop.name3", int{4}},
+  native_types::Object expected1{
+    {"prop.name1", unittests::make_int_prop_value(3)},
+    {"prop.name2", unittests::make_int_prop_value(2)},
+    {"prop.name3", unittests::make_int_prop_value(4)},
   };
   EXPECT_EQ(start_time + time_delta1, changes[0].timestamp);
   EXPECT_EQ(expected1, changes[0].changed_properties);
 
-  chromeos::VariantDictionary expected2{
-    {"prop.name10", int{10}},
-    {"prop.name11", int{11}},
+  native_types::Object expected2{
+    {"prop.name10", unittests::make_int_prop_value(10)},
+    {"prop.name11", unittests::make_int_prop_value(11)},
   };
   EXPECT_EQ(start_time + time_delta2, changes[1].timestamp);
   EXPECT_EQ(expected2, changes[1].changed_properties);
diff --git a/buffet/states/state_manager.cc b/buffet/states/state_manager.cc
index 80fdc8c..b621d02 100644
--- a/buffet/states/state_manager.cc
+++ b/buffet/states/state_manager.cc
@@ -110,7 +110,8 @@
   if (!package->SetPropertyValue(property_name, value, error))
     return false;
 
-  chromeos::VariantDictionary prop_set{{full_property_name, value}};
+  native_types::Object prop_set{{full_property_name,
+                                 package->GetProperty(property_name)}};
   state_change_queue_->NotifyPropertiesUpdated(timestamp, prop_set);
   return true;
 }
diff --git a/buffet/states/state_manager_unittest.cc b/buffet/states/state_manager_unittest.cc
index bdfad8c..b035175 100644
--- a/buffet/states/state_manager_unittest.cc
+++ b/buffet/states/state_manager_unittest.cc
@@ -103,8 +103,8 @@
 }
 
 TEST_F(StateManagerTest, SetPropertyValue) {
-  chromeos::VariantDictionary expected_prop_set{
-    {"terminator.target", std::string{"John Connor"}},
+  native_types::Object expected_prop_set{
+    {"terminator.target", unittests::make_string_prop_value("John Connor")},
   };
   base::Time timestamp = base::Time::Now();
   EXPECT_CALL(mock_state_change_queue_,
@@ -166,8 +166,8 @@
   std::vector<StateChange> expected_val;
   expected_val.emplace_back(
       timestamp,
-      chromeos::VariantDictionary{{"terminator.target",
-                                   std::string{"John Connor"}}});
+      native_types::Object{{"terminator.target",
+                            unittests::make_string_prop_value("John Connor")}});
   EXPECT_CALL(mock_state_change_queue_, GetAndClearRecordedStateChanges())
       .WillOnce(Return(expected_val));
   auto changes = mgr_->GetAndClearRecordedStateChanges();
@@ -177,5 +177,4 @@
             changes.back().changed_properties);
 }
 
-
 }  // namespace buffet
diff --git a/buffet/states/state_package.h b/buffet/states/state_package.h
index b2e1383..1430b5c 100644
--- a/buffet/states/state_package.h
+++ b/buffet/states/state_package.h
@@ -65,6 +65,13 @@
                         const chromeos::Any& value,
                         chromeos::ErrorPtr* error);
 
+  std::shared_ptr<const PropValue>
+  GetProperty(const std::string& property_name) const {
+    auto it = values_.find(property_name);
+    return it != values_.end() ?
+        it->second : std::shared_ptr<const PropValue>{};
+  }
+
   // Returns the name of the this package.
   const std::string& GetName() const { return name_; }