As the first step in an effort to improve robustness of the cloud print proxy...

chrome/common/common_param_traits.h

Index: chrome/common/common_param_traits.h
===================================================================
--- chrome/common/common_param_traits.h	(revision 69859)
+++ chrome/common/common_param_traits.h	(working copy)
@@ -56,6 +56,7 @@
 
 namespace printing {
 struct PageRange;
+struct PrinterCapsAndDefaults;
 }  // namespace printing
 
 namespace webkit_glue {
@@ -334,6 +335,14 @@
   typedef int Type;
 };
 
+template <>
+struct ParamTraits<printing::PrinterCapsAndDefaults> {
+  typedef printing::PrinterCapsAndDefaults param_type;
+  static void Write(Message* m, const param_type& p);
+  static bool Read(const Message* m, void** iter, param_type* r);
+  static void Log(const param_type& p, std::string* l);
+};
+
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_COMMON_PARAM_TRAITS_H_