Add the "virtual" keyword on method overrides that are missing it.

webkit/glue/plugins/pepper_scrollbar.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 "webkit/glue/plugins/pepper_scrollbar.h"
 
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "ppapi/c/dev/ppp_scrollbar_dev.h"
 #include "skia/ext/platform_canvas.h"
@@ skipping 92 matching lines @@
 }
 
 Scrollbar::~Scrollbar() {
 }
 
 // static
 const PPB_Scrollbar_Dev* Scrollbar::GetInterface() {
   return &ppb_scrollbar;
 }
 
+Scrollbar* Scrollbar::AsScrollbar() {
+  return this;
+}
+
 uint32_t Scrollbar::GetValue() {
   return scrollbar_->value();
 }
 
 void Scrollbar::SetValue(uint32_t value) {
   scrollbar_->setValue(value);
 }
 
 void Scrollbar::SetDocumentSize(uint32_t size) {
   scrollbar_->setDocumentSize(size);
@@ skipping 110 matching lines @@
   PP_Rect pp_rect;
   pp_rect.point.x = dirty_.x();
   pp_rect.point.y = dirty_.y();
   pp_rect.size.width = dirty_.width();
   pp_rect.size.height = dirty_.height();
   dirty_ = gfx::Rect();
   Invalidate(&pp_rect);
 }
 
 }  // namespace pepper