replace PhantomJS with headless Chrome as karma test runner

config/karma.config.js

@@ -21,7 +21,7 @@ module.exports = function(config) {
 
   var karmaConfig = {
     basePath: ROOT_PATH,
-    browsers: ['PhantomJS'],
+    browsers: ['ChromeHeadless'],
     frameworks: ['jasmine'],
     files: [
       { pattern: 'spec/javascripts/test_bundle.js', watched: false },

package.json

@@ -75,6 +75,7 @@
     "jasmine-core": "^2.5.2",
     "jasmine-jquery": "^2.1.1",
     "karma": "^1.4.1",
+    "karma-chrome-launcher": "^2.1.1",
     "karma-coverage-istanbul-reporter": "^0.2.0",
     "karma-jasmine": "^1.1.0",
     "karma-mocha-reporter": "^2.2.2",

yarn.lock

@@ -2407,6 +2407,12 @@ from@~0:
   version "0.1.7"
   resolved "https://registry.yarnpkg.com/from/-/from-0.1.7.tgz#83c60afc58b9c56997007ed1a768b3ab303a44fe"
 
+fs-access@^1.0.0:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/fs-access/-/fs-access-1.0.1.tgz#d6a87f262271cefebec30c553407fb995da8777a"
+  dependencies:
+    null-check "^1.0.0"
+
 fs-extra@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-1.0.0.tgz#cd3ce5f7e7cb6145883fcae3191e9877f8587950"
@@ -3261,6 +3267,13 @@ jszip@^3.1.3:
     pako "~1.0.2"
     readable-stream "~2.0.6"
 
+karma-chrome-launcher@^2.1.1:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/karma-chrome-launcher/-/karma-chrome-launcher-2.1.1.tgz#216879c68ac04d8d5140e99619ba04b59afd46cf"
+  dependencies:
+    fs-access "^1.0.0"
+    which "^1.2.1"
+
 karma-coverage-istanbul-reporter@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/karma-coverage-istanbul-reporter/-/karma-coverage-istanbul-reporter-0.2.0.tgz#5766263338adeb0026f7e4ac7a89a5f056c5642c"
@@ -3907,6 +3920,10 @@ npmlog@^4.0.1:
     gauge "~2.7.1"
     set-blocking "~2.0.0"
 
+null-check@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/null-check/-/null-check-1.0.0.tgz#977dffd7176012b9ec30d2a39db5cf72a0439edd"
+
 num2fraction@^1.2.2:
   version "1.2.2"
   resolved "https://registry.yarnpkg.com/num2fraction/-/num2fraction-1.2.2.tgz#6f682b6a027a4e9ddfa4564cd2589d1d4e669ede"
@@ -5883,7 +5900,7 @@ which-module@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/which-module/-/which-module-1.0.0.tgz#bba63ca861948994ff307736089e3b96026c2a4f"
 
-which@^1.1.1, which@~1.2.10:
+which@^1.1.1, which@^1.2.1, which@~1.2.10:
   version "1.2.12"
   resolved "https://registry.yarnpkg.com/which/-/which-1.2.12.tgz#de67b5e450269f194909ef23ece4ebe416fa1192"
   dependencies: