If there is a prebuilt jar that defines a different binary jar from
the gwt jar, building a normal java binary will use the binary jar,
and building a gwt binary will use the gwt jar.
If a target defines them both to be the same there's no need to define
the gwt jar, as it will default to being the binary jar.
The actual use case where it is needed when there is an alternative GWT
implementation of a Java library. Specifically, when there is one
implementation that contains JSNI, and one implementation that contains
an implementation that cannot be translated to JS by the GWT compiler:
prebuilt_jar(
name = 'guava',
binary_jar = 'guava-17.0.jar',
source_jar = 'guava-17.0-sources.jar',
gwt_jar = 'guava-gwt-17.0.jar',
visibility = [
'PUBLIC',
],
)
Change-Id: Ibbc7ea56aad6885625e652b2dedbcdfe038735d7
b0924cafe7