Enable Closure Compiler when building ui_opt

GWT 2.5 adds the option to optimize the generated JavaScript
even further with Closure Compiler. Pass -XenableClosureCompiler
to enable this when building ui_opt.

This reduces the size of gerrit.war built from current master by
~100k at the expense of increased build time. The optimized
JavaScript should also run faster.

Change-Id: I73343786e36a49dd3d9f9a733309248aedcd2a46
1 file changed