message: Clearer message when output shape can't be inferred.
diff: @@ -738,7 +738,9 @@ class Layer(module.Module, version_utils.LayerVersionSelector):
  '`compute_output_shape` method on your layer (%s).' %
  self.__class__.__name__), e)
  return nest.map_structure(lambda t: t.shape, outputs)
  - raise NotImplementedError
  + raise NotImplementedError(
  + 'Please run in eager mode or implement the `compute_output_shape` '
  + 'method on your layer (%s).' % self.__class__.__name__)
  @doc_controls.for_subclass_implementers
  def compute_output_signature(self, input_signature):
  