message: Don't require geometry buffers to be staged
diff: @@ -115,9 +115,6 @@ namespace dawn_native {
  }
  // validate vertex input
  if (geometry.vertex != nullptr) {
  - if ((geometry.vertex->buffer->GetUsage() & wgpu::BufferUsage::CopyDst) == 0) {
  - return DAWN_VALIDATION_ERROR("Vertex data must be staged");
  - }
  if (geometry.vertex->buffer->GetSize() == 0) {
  return DAWN_VALIDATION_ERROR("Invalid Buffer for Vertex data");
  }
  @@ -133,9 +130,6 @@ namespace dawn_native {
  if (geometry.index->buffer->GetSize() == 0) {
  return DAWN_VALIDATION_ERROR("Invalid Buffer for Index data");
  }
  - if ((geometry.index->buffer->GetUsage() & wgpu::BufferUsage::CopyDst) == 0) {
  - return DAWN_VALIDATION_ERROR("Index data must be staged");
  - }
  if (geometry.index->count == 0) {
  return DAWN_VALIDATION_ERROR("Index count must not be zero");
  }
  @@ -153,9 +147,6 @@ namespace dawn_native {
  if (geometry.aabb->buffer->GetSize() == 0) {
  return DAWN_VALIDATION_ERROR("Invalid Buffer for AABB data");
  }
  - if ((geometry.aabb->buffer->GetUsage() & wgpu::BufferUsage::CopyDst) == 0) {
  - return DAWN_VALIDATION_ERROR("AABB data must be staged");
  - }
  if (geometry.aabb->count == 0) {
  return DAWN_VALIDATION_ERROR("AABB count must not be zero");
  }
  