Fix race condition with windowless plugin buffers. The problem, which is already fixed for Mac, is …

content/plugin/webplugin_proxy.h

Index: content/plugin/webplugin_proxy.h
===================================================================
--- content/plugin/webplugin_proxy.h	(revision 151213)
+++ content/plugin/webplugin_proxy.h	(working copy)
@@ -19,6 +19,7 @@
 #include "base/timer.h"
 #include "googleurl/src/gurl.h"
 #include "ipc/ipc_message.h"
+#include "third_party/skia/include/core/SkRefCnt.h"
 #if defined(USE_X11)
 #include "ui/base/x/x11_util.h"
 #endif
@@ -207,7 +208,7 @@
 #if defined(OS_WIN)
   void CreateCanvasFromHandle(const TransportDIB::Handle& dib_handle,
                               const gfx::Rect& window_rect,
-                              scoped_ptr<skia::PlatformCanvas>* canvas_out);
+                              SkRefPtr<skia::PlatformCanvas>* canvas);
 #elif defined(OS_MACOSX)
   static void CreateDIBAndCGContextFromHandle(
       const TransportDIB::Handle& dib_handle,
@@ -219,7 +220,7 @@
       const TransportDIB::Handle& dib_handle,
       const gfx::Rect& window_rect,
       scoped_ptr<TransportDIB>* dib_out,
-      scoped_ptr<skia::PlatformCanvas>* canvas_out);
+      SkRefPtr<skia::PlatformCanvas>* canvas);
 
   static void CreateShmPixmapFromDIB(
       TransportDIB* dib,
@@ -279,8 +280,8 @@
   base::mac::ScopedCFTypeRef<CGContextRef> background_context_;
   scoped_ptr<WebPluginAcceleratedSurfaceProxy> accelerated_surface_;
 #else
-  scoped_ptr<skia::PlatformCanvas> windowless_canvases_[2];
-  scoped_ptr<skia::PlatformCanvas> background_canvas_;
+  SkRefPtr<skia::PlatformCanvas> windowless_canvases_[2];
+  SkRefPtr<skia::PlatformCanvas> background_canvas_;
 
 #if defined(USE_X11)
   scoped_ptr<TransportDIB> windowless_dibs_[2];