Support add-on 'field trial' records.

components/metrics/persistent_system_profile_unittest.cc

Index: components/metrics/persistent_system_profile_unittest.cc
diff --git a/components/metrics/persistent_system_profile_unittest.cc b/components/metrics/persistent_system_profile_unittest.cc
index a2e038a47d2ebc5791e69dc9eeff42d2e9cf8ec6..8c1b6b03d63e7d665c08fe04c37e280539634637 100644
--- a/components/metrics/persistent_system_profile_unittest.cc
+++ b/components/metrics/persistent_system_profile_unittest.cc
@@ -8,6 +8,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/metrics/persistent_memory_allocator.h"
 #include "base/rand_util.h"
+#include "components/variations/metrics_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace metrics {
@@ -134,4 +135,37 @@ TEST_F(PersistentSystemProfileTest, ProfileStorage) {
   EXPECT_EQ(90U, proto2.field_trial(1).group_id());
 }
 
+TEST_F(PersistentSystemProfileTest, ProfileExtensions) {
+  persistent_profile()->SetFieldTrial("sna", "foo");
+
+  SystemProfileProto fetched;
+  ASSERT_FALSE(
+      PersistentSystemProfile::GetSystemProfile(*memory_allocator(), &fetched));
+
+  SystemProfileProto proto;
+  SystemProfileProto::FieldTrial* trial = proto.add_field_trial();
+  trial->set_name_id(123);
+  trial->set_group_id(456);
+
+  persistent_profile()->SetSystemProfile(proto, false);
+  ASSERT_TRUE(
+      PersistentSystemProfile::GetSystemProfile(*memory_allocator(), &fetched));
+  ASSERT_EQ(2, fetched.field_trial_size());
+  EXPECT_EQ(123U, fetched.field_trial(0).name_id());
+  EXPECT_EQ(456U, fetched.field_trial(0).group_id());
+  EXPECT_EQ(metrics::HashName("sna"), fetched.field_trial(1).name_id());
+  EXPECT_EQ(metrics::HashName("foo"), fetched.field_trial(1).group_id());
+
+  persistent_profile()->SetFieldTrial("foo", "bar");
+  ASSERT_TRUE(
+      PersistentSystemProfile::GetSystemProfile(*memory_allocator(), &fetched));
+  ASSERT_EQ(3, fetched.field_trial_size());
+  EXPECT_EQ(123U, fetched.field_trial(0).name_id());
+  EXPECT_EQ(456U, fetched.field_trial(0).group_id());
+  EXPECT_EQ(metrics::HashName("sna"), fetched.field_trial(1).name_id());
+  EXPECT_EQ(metrics::HashName("foo"), fetched.field_trial(1).group_id());
+  EXPECT_EQ(metrics::HashName("foo"), fetched.field_trial(2).name_id());
+  EXPECT_EQ(metrics::HashName("bar"), fetched.field_trial(2).group_id());
+}
+
 }  // namespace metrics