Pepper and WebKit API change to support a plugin knowing if a scrollbar is an overlay one.

ppapi/cpp/dev/scrollbar_dev.cc

Index: ppapi/cpp/dev/scrollbar_dev.cc
===================================================================
--- ppapi/cpp/dev/scrollbar_dev.cc	(revision 95773)
+++ ppapi/cpp/dev/scrollbar_dev.cc	(working copy)
@@ -6,6 +6,7 @@
 
 #include "ppapi/cpp/dev/scrollbar_dev.h"
 
+#include "ppapi/cpp/dev/scrollbar_group_dev.h"
 #include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/module.h"
 #include "ppapi/cpp/module_impl.h"
@@ -24,11 +25,12 @@
 Scrollbar_Dev::Scrollbar_Dev(PP_Resource resource) : Widget_Dev(resource) {
 }
 
-Scrollbar_Dev::Scrollbar_Dev(const Instance& instance, bool vertical) {
+Scrollbar_Dev::Scrollbar_Dev(const ScrollbarGroup_Dev& scrollbar_group,
+                             bool vertical) {
   if (!has_interface<PPB_Scrollbar_Dev>())
     return;
   PassRefFromConstructor(get_interface<PPB_Scrollbar_Dev>()->Create(
-      instance.pp_instance(), PP_FromBool(vertical)));
+      scrollbar_group.pp_resource(), PP_FromBool(vertical)));
 }
 
 Scrollbar_Dev::Scrollbar_Dev(const Scrollbar_Dev& other)
@@ -41,6 +43,13 @@
   return get_interface<PPB_Scrollbar_Dev>()->GetThickness(pp_resource());
 }
 
+bool Scrollbar_Dev::IsOverlay() {
+  if (!has_interface<PPB_Scrollbar_Dev>())
+    return false;
+  return
+      PP_ToBool(get_interface<PPB_Scrollbar_Dev>()->IsOverlay(pp_resource()));
+}
+
 uint32_t Scrollbar_Dev::GetValue() {
   if (!has_interface<PPB_Scrollbar_Dev>())
     return 0;