Take advantage of MojoGetBufferInformation

mojo/services/media/common/cpp/circular_buffer_media_pipe_adapter.cc

 // Copyright 2015 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/public/cpp/environment/logging.h"
 #include "mojo/public/cpp/utility/run_loop.h"
 #include "mojo/services/media/common/cpp/circular_buffer_media_pipe_adapter.h"
 #include "mojo/services/media/common/interfaces/media_common.mojom.h"
 #include "mojo/services/media/common/interfaces/media_transport.mojom.h"
 
@@ skipping 97 matching lines @@
   // read-only.
   ScopedSharedBufferHandle duplicated_handle;
   res = DuplicateBuffer(buffer_handle_.get(), nullptr, &duplicated_handle);
   if (res != MOJO_RESULT_OK) {
     MOJO_LOG(ERROR) << "Failed to duplicate handle in " << __PRETTY_FUNCTION__
                     << " (error " << res << ")";
     Fault(MediaResult::UNKNOWN_ERROR);
     return;
   }
 
-  // TODO(johngro) : We should not have to send the buffer size, it should be an
-  // intrinsic property of the buffer itself and be query-able via the handle.
-  pipe_->SetBuffer(duplicated_handle.Pass(), buffer_size_, []() {});
+  pipe_->SetBuffer(duplicated_handle.Pass(), []() {});
 }
 
 void CircularBufferMediaPipeAdapter::SetSignalCallback(SignalCbk cbk) {
   bool schedule;
   signal_cbk_ = cbk;
   schedule = (signal_cbk_ != nullptr);
 
   // If the user supplied a non-null callback, make sure we schedule a
   // callback if we are currently signalled.
   if (schedule) {
@@ skipping 386 matching lines @@
 uint64_t CircularBufferMediaPipeAdapter::GetBufferSize() const {
   if (nullptr == buffer_)
     return 0;
 
   MOJO_DCHECK(buffer_size_);
   return buffer_size_ - 1;
 }
 
 }  // namespace media
 }  // namespace mojo