Adding previews information to PLM UKM

components/ukm/public/ukm_recorder.h

Index: components/ukm/public/ukm_recorder.h
diff --git a/components/ukm/public/ukm_recorder.h b/components/ukm/public/ukm_recorder.h
index bcb5a4d2df1fa21565e8ed486e12c950175e68aa..3adbaa5f4236fbb5aef1aa743a4cd74b865d208e 100644
--- a/components/ukm/public/ukm_recorder.h
+++ b/components/ukm/public/ukm_recorder.h
@@ -18,6 +18,7 @@
 
 class ContextualSearchRankerLoggerImpl;
 class PluginInfoMessageFilter;
+class PreviewsInfoBarDelegate;
 class UkmPageLoadMetricsObserver;
 
 namespace autofill {
@@ -42,6 +43,10 @@ namespace password_manager {
 class PasswordFormMetricsRecorder;
 }
 
+namespace previews {
+class PreviewsUKMObserver;
+}
+
 namespace ukm {
 
 class UkmEntryBuilder;
@@ -85,6 +90,8 @@ class UKM_EXPORT UkmRecorder {
   friend content::RenderFrameImpl;
   friend content::RenderWidgetHostLatencyTracker;
   friend password_manager::PasswordFormMetricsRecorder;
+  friend PreviewsInfoBarDelegate;
+  friend previews::PreviewsUKMObserver;
   FRIEND_TEST_ALL_PREFIXES(UkmServiceTest, AddEntryWithEmptyMetrics);
   FRIEND_TEST_ALL_PREFIXES(UkmServiceTest, EntryBuilderAndSerialization);
   FRIEND_TEST_ALL_PREFIXES(UkmServiceTest,