Material PDF: Add metrics to count usage of PDF title and bookmarks

pdf/out_of_process_instance.cc

Index: pdf/out_of_process_instance.cc
diff --git a/pdf/out_of_process_instance.cc b/pdf/out_of_process_instance.cc
index cfa11ba980be40c03c854e760bb54365d3a76219..1d1f1f89970f7bb8eb9da2349ad0c76b9eac967d 100644
--- a/pdf/out_of_process_instance.cc
+++ b/pdf/out_of_process_instance.cc
@@ -1112,10 +1112,16 @@ void OutOfProcessInstance::DocumentLoadComplete(int page_count) {
   pp::VarDictionary metadata_message;
   metadata_message.Set(pp::Var(kType), pp::Var(kJSMetadataType));
   std::string title = engine_->GetMetadata("Title");
-  if (!base::TrimWhitespace(base::UTF8ToUTF16(title), base::TRIM_ALL).empty())
+  bool has_title =
+      !base::TrimWhitespace(base::UTF8ToUTF16(title), base::TRIM_ALL).empty();
+  if (has_title)
     metadata_message.Set(pp::Var(kJSTitle), pp::Var(title));
+  uma_.HistogramEnumeration("PDF.HasFeature.Title", has_title ? 1 : 0, 2);
 
-  metadata_message.Set(pp::Var(kJSBookmarks), engine_->GetBookmarks());
+  pp::VarArray bookmarks = engine_->GetBookmarks();
+  metadata_message.Set(pp::Var(kJSBookmarks), bookmarks);
+  uma_.HistogramEnumeration("PDF.HasFeature.Bookmarks",
+                            bookmarks.GetLength() > 0 ? 1 : 0, 2);
   PostMessage(metadata_message);
 
   pp::VarDictionary progress_message;