Remove support for "all or none" two-phase data pipe read/write.

mojo/edk/system/data_pipe_consumer_dispatcher.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/edk/system/data_pipe_consumer_dispatcher.h"
 
 #include "base/logging.h"
 #include "mojo/edk/system/data_pipe.h"
 #include "mojo/edk/system/memory.h"
 
@@ skipping 89 matching lines @@
       !!(flags & MOJO_READ_DATA_FLAG_PEEK));
 }
 
 MojoResult DataPipeConsumerDispatcher::BeginReadDataImplNoLock(
     UserPointer<const void*> buffer,
     UserPointer<uint32_t> buffer_num_bytes,
     MojoReadDataFlags flags) {
   mutex().AssertHeld();
 
   // These flags may not be used in two-phase mode.
-  if ((flags & MOJO_READ_DATA_FLAG_DISCARD) ||
+  if ((flags & MOJO_READ_DATA_FLAG_ALL_OR_NONE) ||
+      (flags & MOJO_READ_DATA_FLAG_DISCARD) ||
       (flags & MOJO_READ_DATA_FLAG_QUERY) || (flags & MOJO_READ_DATA_FLAG_PEEK))
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  return data_pipe_->ConsumerBeginReadData(
-      buffer, buffer_num_bytes, (flags & MOJO_READ_DATA_FLAG_ALL_OR_NONE));
+  // TODO(vtl): Remove all-or-none support at lower levels.
+  return data_pipe_->ConsumerBeginReadData(buffer, buffer_num_bytes, false);
 }
 
 MojoResult DataPipeConsumerDispatcher::EndReadDataImplNoLock(
     uint32_t num_bytes_read) {
   mutex().AssertHeld();
 
   return data_pipe_->ConsumerEndReadData(num_bytes_read);
 }
 
 HandleSignalsState DataPipeConsumerDispatcher::GetHandleSignalsStateImplNoLock()
@@ skipping 40 matching lines @@
   return rv;
 }
 
 bool DataPipeConsumerDispatcher::IsBusyNoLock() const {
   mutex().AssertHeld();
   return data_pipe_->ConsumerIsBusy();
 }
 
 }  // namespace system
 }  // namespace mojo