background-color excluded from closure-compile if occurs before background: linear-gradient

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What steps will reproduce the problem?
1. create the following css style 
.cssButton {background-color: #00853f; background: linear-gradient(0deg, 
#00853f, #7BAE3B ); }

2. Run the google closure compiler (version 20111230.jar) against this style

3.  The background-color style is ignored without warning and excluded from the 
compiled-output-file

4. If you place the background-color AFTER the background: linear-gradient(...) 
style... then the compiler at least puts both styles into the compiled output 

What is the expected output? What do you see instead?
expected output is a possible warning or error indicating that the 
background-color attribute will be ignored or excluded from the output-file

What version of the product are you using? On what operating system?
(version 20111230.jar) running on SunOS 5.10 with jre1.6.0_33

Please provide any additional information below.
it's possible that the compiler is correct in excluding the background-color in 
favor of the abbreviated syntax "background:...." style but there should be a 
warning or error thrown.

Original issue reported on code.google.com by ericjric...@gmail.com on 21 Jun 2013 at 6:00