fix: Show error for a missing dependency.
fix: Show error for a missing dependency.

This ensures that something is printed out for users who didn't add a mapping for one of their dependencies. Either they missed a deps.js file or they didn't preprocess all of their source files. The current behavior adds an undefined filepath which ends up causing the karma web-server to blow up when it trys to do indexOf on undefined.

selkhateeb/karma-closure,alexg-dev/karma-closure,karma-runner/karma-closure,airtimemedia/karma-closure,hikirsch/karma-closure,airtimemedia/karma-closure,karma-runner/karma-closure,alexg-dev/karma-closure,hikirsch/karma-closure,selkhateeb/karma-closure