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

mojo/system/data_pipe.cc

 // 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.
 
 #include "mojo/system/data_pipe.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 268 matching lines @@
   base::AutoLock locker(lock_);
   DCHECK(has_local_consumer_no_lock());
 
   if (consumer_in_two_phase_read_no_lock())
     return MOJO_RESULT_BUSY;
 
   // Note: Don't need to validate |*num_bytes| for query.
   return ConsumerQueryDataImplNoLock(num_bytes);
 }
 
-MojoResult DataPipe::ConsumerBeginReadData(const void** buffer,
-                                           uint32_t* buffer_num_bytes,
-                                           bool all_or_none) {
+MojoResult DataPipe::ConsumerBeginReadData(
+    UserPointer<const void*> buffer,
+    UserPointer<uint32_t> buffer_num_bytes,
+    bool all_or_none) {
   base::AutoLock locker(lock_);
   DCHECK(has_local_consumer_no_lock());
 
   if (consumer_in_two_phase_read_no_lock())
     return MOJO_RESULT_BUSY;
 
-  if (all_or_none && *buffer_num_bytes % element_num_bytes_ != 0)
-    return MOJO_RESULT_INVALID_ARGUMENT;
+  uint32_t min_num_bytes_to_read = 0;
+  if (all_or_none) {
+    min_num_bytes_to_read = buffer_num_bytes.Get();
+    if (min_num_bytes_to_read % element_num_bytes_ != 0)
+      return MOJO_RESULT_INVALID_ARGUMENT;
+  }
 
   MojoResult rv = ConsumerBeginReadDataImplNoLock(buffer, buffer_num_bytes,
-                                                  all_or_none);
+                                                  min_num_bytes_to_read);
   if (rv != MOJO_RESULT_OK)
     return rv;
   DCHECK(consumer_in_two_phase_read_no_lock());
   return MOJO_RESULT_OK;
 }
 
 MojoResult DataPipe::ConsumerEndReadData(uint32_t num_bytes_read) {
   base::AutoLock locker(lock_);
   DCHECK(has_local_consumer_no_lock());
 
@@ skipping 86 matching lines @@
 void DataPipe::AwakeConsumerWaitersForStateChangeNoLock(
     const HandleSignalsState& new_consumer_state) {
   lock_.AssertAcquired();
   if (!has_local_consumer_no_lock())
     return;
   consumer_waiter_list_->AwakeWaitersForStateChange(new_consumer_state);
 }
 
 }  // namespace system
 }  // namespace mojo