Convert ReadData...() to use the new user pointer handling (see r285350).

mojo/system/dispatcher.h

 // Copyright 2013 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.
 
 #ifndef MOJO_SYSTEM_DISPATCHER_H_
 #define MOJO_SYSTEM_DISPATCHER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 81 matching lines @@
                          DispatcherVector* dispatchers,
                          uint32_t* num_dispatchers,
                          MojoReadMessageFlags flags);
   MojoResult WriteData(const void* elements,
                        uint32_t* elements_num_bytes,
                        MojoWriteDataFlags flags);
   MojoResult BeginWriteData(UserPointer<void*> buffer,
                             UserPointer<uint32_t> buffer_num_bytes,
                             MojoWriteDataFlags flags);
   MojoResult EndWriteData(uint32_t num_bytes_written);
-  MojoResult ReadData(void* elements,
-                      uint32_t* num_bytes,
+  MojoResult ReadData(UserPointer<void> elements,
+                      UserPointer<uint32_t> num_bytes,
                       MojoReadDataFlags flags);
   MojoResult BeginReadData(UserPointer<const void*> buffer,
                            UserPointer<uint32_t> buffer_num_bytes,
                            MojoReadDataFlags flags);
   MojoResult EndReadData(uint32_t num_bytes_read);
   // |options| may be null. |new_dispatcher| must not be null, but
   // |*new_dispatcher| should be null (and will contain the dispatcher for the
   // new handle on success).
   MojoResult DuplicateBufferHandle(
       const MojoDuplicateBufferHandleOptions* options,
@@ skipping 109 matching lines @@
                                            uint32_t* num_dispatchers,
                                            MojoReadMessageFlags flags);
   virtual MojoResult WriteDataImplNoLock(const void* elements,
                                          uint32_t* num_bytes,
                                          MojoWriteDataFlags flags);
   virtual MojoResult BeginWriteDataImplNoLock(
       UserPointer<void*> buffer,
       UserPointer<uint32_t> buffer_num_bytes,
       MojoWriteDataFlags flags);
   virtual MojoResult EndWriteDataImplNoLock(uint32_t num_bytes_written);
-  virtual MojoResult ReadDataImplNoLock(void* elements,
-                                        uint32_t* num_bytes,
+  virtual MojoResult ReadDataImplNoLock(UserPointer<void> elements,
+                                        UserPointer<uint32_t> num_bytes,
                                         MojoReadDataFlags flags);
   virtual MojoResult BeginReadDataImplNoLock(
       UserPointer<const void*> buffer,
       UserPointer<uint32_t> buffer_num_bytes,
       MojoReadDataFlags flags);
   virtual MojoResult EndReadDataImplNoLock(uint32_t num_bytes_read);
   virtual MojoResult DuplicateBufferHandleImplNoLock(
       const MojoDuplicateBufferHandleOptions* options,
       scoped_refptr<Dispatcher>* new_dispatcher);
   virtual MojoResult MapBufferImplNoLock(
@@ skipping 128 matching lines @@
 
   Dispatcher* dispatcher_;
 
   // Copy and assign allowed.
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_DISPATCHER_H_