PDF Printing: embed browser user agent string in PDF metadata.

printing/print_settings.cc

Index: printing/print_settings.cc
diff --git a/printing/print_settings.cc b/printing/print_settings.cc
index b1c50c9e372bf9fa0008e1b1a568323ee995e906..7f555f0d88288f762e800f4e7bce0221fc18785d 100644
--- a/printing/print_settings.cc
+++ b/printing/print_settings.cc
@@ -5,12 +5,23 @@
 #include "printing/print_settings.h"
 
 #include "base/atomic_sequence_num.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "printing/print_job_constants.h"
 #include "printing/units.h"
 
 namespace printing {
 
+base::LazyInstance<std::string> g_user_agent;
+
+void SetAgent(const std::string& user_agent) {
+  g_user_agent.Get() = user_agent;
+}
+
+const std::string& GetAgent() {
+  return g_user_agent.Get();
+}
+
 #if defined(USE_CUPS)
 void GetColorModelForMode(
     int color_mode, std::string* color_setting_name, std::string* color_value) {