PPAPI: Make blocking completion callbacks work.

webkit/plugins/ppapi/ppapi_plugin_instance.h

Index: webkit/plugins/ppapi/ppapi_plugin_instance.h
diff --git a/webkit/plugins/ppapi/ppapi_plugin_instance.h b/webkit/plugins/ppapi/ppapi_plugin_instance.h
index dc430e713daaeb3627a6c548ecfedfa5fd5ed177..165ac4630a89300a894df4a12c7560fd1ab3d010 100644
--- a/webkit/plugins/ppapi/ppapi_plugin_instance.h
+++ b/webkit/plugins/ppapi/ppapi_plugin_instance.h
@@ -38,6 +38,7 @@
 #include "ppapi/shared_impl/function_group_base.h"
 #include "ppapi/shared_impl/ppb_instance_shared.h"
 #include "ppapi/shared_impl/ppb_view_shared.h"
+#include "ppapi/shared_impl/tracked_callback.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebCanvas.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebString.h"
@@ -381,7 +382,7 @@ class WEBKIT_PLUGINS_EXPORT PluginInstance :
                             PP_Resource image,
                             const PP_Point* hot_spot) OVERRIDE;
   virtual int32_t LockMouse(PP_Instance instance,
-                            PP_CompletionCallback callback) OVERRIDE;
+                            ::ppapi::ApiCallbackType callback) OVERRIDE;
   virtual void UnlockMouse(PP_Instance instance) OVERRIDE;
   virtual PP_Var ResolveRelativeToDocument(
       PP_Instance instance,
@@ -642,7 +643,7 @@ class WEBKIT_PLUGINS_EXPORT PluginInstance :
   size_t selection_caret_;
   size_t selection_anchor_;
 
-  PP_CompletionCallback lock_mouse_callback_;
+  scoped_refptr< ::ppapi::TrackedCallback> lock_mouse_callback_;
 
   // Track pending user gestures so out-of-process plugins can respond to
   // a user gesture after it has been processed.