Previously, comments were not used as a parameter in the computed
function that calculated patch range values. Instead, it just used the
value of 'comments' when the patch dropdown was computed.
However, if comments were loaded after the dropdown values were
calculated, it was not updated to display the comment counts.
This change fixes the problem by using comments as a parameter in the
value calculations, and includes a default empty object in the case that
comments are not used as an input for the patch range selector
(currently the diff view).
Bug: Issue 7444
Change-Id: I2646800afc1632bf39b3c6a451c848669007ca18
3a90cd92c2