message: Removed Context._tld.mode
  It has zero usages outside of Context and duplicates Context._tld.is_eager
diff: @@ -177,7 +177,6 @@ class _ThreadLocalData(threading.local):
  super(_ThreadLocalData, self).__init__()
  self.device_spec = _starting_device_spec
  self.device_name = ""
  - self.mode = default_execution_mode
  self.is_eager = default_execution_mode == EAGER_MODE
  self.scope_name = ""
  self.summary_writer = None
  @@ -633,9 +632,7 @@ class Context(object):
  def _mode(self, mode):
  """A context manager to allow setting the mode to EAGER/GRAPH."""
  ctx = self._thread_local_data
  - old_mode = ctx.mode
  old_is_eager = ctx.is_eager
  - ctx.mode = mode
  ctx.is_eager = mode == EAGER_MODE
  if mode == EAGER_MODE:
  # Entering graph mode does not provide us with sufficient information to
  @@ -646,7 +643,6 @@ class Context(object):
  yield
  finally:
  ctx.is_eager = old_is_eager
  - ctx.mode = old_mode
  if mode == EAGER_MODE:
  self.context_switches.pop()
  