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

ppapi/cpp/dev/scrollbar_dev.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <vector>
 
 #include "ppapi/cpp/dev/scrollbar_dev.h"
 
 #include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/module.h"
@@ skipping 23 matching lines @@
 Scrollbar_Dev::Scrollbar_Dev(const Scrollbar_Dev& other)
     : Widget_Dev(other) {
 }
 
 uint32_t Scrollbar_Dev::GetThickness() {
   if (!has_interface<PPB_Scrollbar_Dev>())
     return 0;
   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;
   return get_interface<PPB_Scrollbar_Dev>()->GetValue(pp_resource());
 }
 
 void Scrollbar_Dev::SetValue(uint32_t value) {
   if (has_interface<PPB_Scrollbar_Dev>())
     get_interface<PPB_Scrollbar_Dev>()->SetValue(pp_resource(), value);
 }
@@ skipping 17 matching lines @@
 }
 
 void Scrollbar_Dev::ScrollBy(PP_ScrollBy_Dev unit, int32_t multiplier) {
   if (has_interface<PPB_Scrollbar_Dev>())
     get_interface<PPB_Scrollbar_Dev>()->ScrollBy(pp_resource(),
                                                  unit,
                                                  multiplier);
 }
 
 }  // namespace pp