Relanding this as the previous attempt failed due to build errors.

webkit/plugins/ppapi/ppb_scrollbar_impl.cc

 // Copyright (c) 2012 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/plugins/ppapi/ppb_scrollbar_impl.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "ppapi/c/dev/ppp_scrollbar_dev.h"
 #include "ppapi/thunk/thunk.h"
 #include "skia/ext/platform_canvas.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebCanvas.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebRect.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebVector.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPluginScrollbar.h"
 #include "webkit/plugins/ppapi/common.h"
 #include "webkit/plugins/ppapi/event_conversion.h"
 #include "webkit/plugins/ppapi/plugin_module.h"
 #include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
 #include "webkit/plugins/ppapi/ppb_image_data_impl.h"
 #include "webkit/plugins/ppapi/resource_helper.h"
@@ skipping 109 matching lines @@
 }
 
 PP_Bool PPB_Scrollbar_Impl::PaintInternal(const gfx::Rect& rect,
                                           PPB_ImageData_Impl* image) {
   ImageDataAutoMapper mapper(image);
   skia::PlatformCanvas* canvas = image->GetPlatformCanvas();
   if (!canvas || !scrollbar_)
     return PP_FALSE;
   canvas->save();
   canvas->scale(scale(), scale());
-  scrollbar_->paint(webkit_glue::ToWebCanvas(canvas), rect);
+  scrollbar_->paint(canvas, rect);
   canvas->restore();
 
 #if defined(OS_WIN)
   if (base::win::GetVersion() == base::win::VERSION_XP)
     skia::MakeOpaque(canvas, rect.x(), rect.y(), rect.width(), rect.height());
 #endif
 
   return PP_TRUE;
 }
 
@@ skipping 88 matching lines @@
   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 ppapi
 }  // namespace webkit