components: Add out-of-line copy ctors for complex classes.

components/printing/common/print_messages.h

Index: components/printing/common/print_messages.h
diff --git a/components/printing/common/print_messages.h b/components/printing/common/print_messages.h
index 2cbffeb882a5fa987da94306c9b95f65452ee1d2..771a4c530c5217fe96576f81002fbaa0c224323f 100644
--- a/components/printing/common/print_messages.h
+++ b/components/printing/common/print_messages.h
@@ -31,6 +31,7 @@
 
 struct PrintMsg_Print_Params {
   PrintMsg_Print_Params();
+  PrintMsg_Print_Params(const PrintMsg_Print_Params& other);
   ~PrintMsg_Print_Params();
 
   // Resets the members of the struct to 0.
@@ -59,6 +60,7 @@ struct PrintMsg_Print_Params {
 
 struct PrintMsg_PrintPages_Params {
   PrintMsg_PrintPages_Params();
+  PrintMsg_PrintPages_Params(const PrintMsg_PrintPages_Params& other);
   ~PrintMsg_PrintPages_Params();
 
   // Resets the members of the struct to 0.