It seems that both comments for sourcemap are needed.
The first one is presented in generator-closure already, the second one needs to be added.
The Chrome Canary doesn't perform the additional GET to sourcemap with appropriate option enabled without the latest comment.
Put please your attention on the 1) absolute path and 2) the absence of app prefix
change sourceMap format, fixes #23
@xasima fixed all issues you raised, sourcemaps needed an updated indeed thanks!
The other errors resulted from the compilation by a custom Closure Compiler which was rigged so it would strip all logs off the build. I reverted back to the vanilla Closure Compiler, which will include all the logging facilities in the final build...
I should take the time to update the custom Closure Compiler build. Will not happen in the foreseeable future...
Needs to reopen
You missed to specify the sourceMappingURL in the fix
saw it and fixed on SHA: 7355ab4