[Chrome] Support NumCopies print preset

ppapi/cpp/dev/printing_dev.cc

Index: ppapi/cpp/dev/printing_dev.cc
diff --git a/ppapi/cpp/dev/printing_dev.cc b/ppapi/cpp/dev/printing_dev.cc
index 60154cd0d37f85f58d5e3115322cd56b67c6760d..ff31fde0a1bff43e723511111fc33cab8b2fba1b 100644
--- a/ppapi/cpp/dev/printing_dev.cc
+++ b/ppapi/cpp/dev/printing_dev.cc
@@ -65,13 +65,17 @@ PP_Bool IsScalingDisabled(PP_Instance instance) {
   return PP_FromBool(return_value);
 }
 
-const PPP_Printing_Dev ppp_printing = {
-  &QuerySupportedFormats,
-  &Begin,
-  &PrintPages,
-  &End,
-  &IsScalingDisabled
-};
+int32_t NumCopies(PP_Instance instance) {
+  void* object =
+      pp::Instance::GetPerInstanceObject(instance, kPPPPrintingInterface);
+  if (!object)
+    return 1;
+  return static_cast<Printing_Dev*>(object)->GetNumCopies();
+}
+
+const PPP_Printing_Dev ppp_printing = {&QuerySupportedFormats, &Begin,
+                                       &PrintPages,            &End,
+                                       &IsScalingDisabled,     &NumCopies};
 
 }  // namespace