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

printing/print_settings.h

Index: printing/print_settings.h
diff --git a/printing/print_settings.h b/printing/print_settings.h
index 1f35e90b9ae0b29bf7c6eedb2fbede9170f7562a..08c7d562c8d69b12e2f394b48df7f73a88a33b2f 100644
--- a/printing/print_settings.h
+++ b/printing/print_settings.h
@@ -26,6 +26,11 @@ PRINTING_EXPORT void GetColorModelForMode(int color_mode,
                                           std::string* color_value);
 #endif
 
+// Inform the printing system that it may embed this user-agent string
+// in its output's metadata.
+PRINTING_EXPORT void SetAgent(const std::string& user_agent);
+PRINTING_EXPORT const std::string& GetAgent();
+
 // OS-independent print settings.
 class PRINTING_EXPORT PrintSettings {
  public: