Add new MouseCursor interface for setting the mouse cursor.

ppapi/shared_impl/ppb_instance_shared.h

Index: ppapi/shared_impl/ppb_instance_shared.h
diff --git a/ppapi/shared_impl/ppb_instance_shared.h b/ppapi/shared_impl/ppb_instance_shared.h
index 2842160528849a2e6ca1c96273aa101e988114b1..8260a784c016dca58cc9a70ed8da9f204d3fb967 100644
--- a/ppapi/shared_impl/ppb_instance_shared.h
+++ b/ppapi/shared_impl/ppb_instance_shared.h
@@ -29,6 +29,10 @@ class PPAPI_SHARED_EXPORT PPB_Instance_Shared
   // Error checks the given resquest to Request[Filtering]InputEvents. Returns
   // PP_OK if the given classes are all valid, PP_ERROR_NOTSUPPORTED if not.
   int32_t ValidateRequestInputEvents(bool is_filtering, uint32_t event_classes);
+
+  bool ValidateSetCursorParams(PP_MouseCursor_Type type,
+                               PP_Resource image,
+                               const PP_Point* hot_spot);
 };
 
 }  // namespace ppapi