Add run script to generate instrumented code coverage .asar

package.json

@@ -24,6 +24,7 @@
   "scripts": {
     "bootstrap": "python ./script/bootstrap.py",
     "build": "python ./script/build.py -c D",
+    "instrument-code-coverage": "node ./spec/coverage/instrument.js",
     "lint": "npm run lint-js && npm run lint-cpp && npm run lint-docs",
     "lint-js": "standard && cd spec && standard",
     "lint-cpp": "python ./script/cpplint.py",

spec/coverage/instrument.js

@@ -0,0 +1,31 @@
+// Generate an instrumented .asar file for all the files in lib/ and save it
+// to out/coverage/electron-instrumented.asar
+
+var asar = require('asar')
+var fs = require('fs')
+var glob = require('glob')
+var Instrumenter = require('istanbul').Instrumenter
+var mkdirp = require('mkdirp')
+var path = require('path')
+
+var instrumenter = new Instrumenter()
+var outputPath = path.join(__dirname, '..', '..', 'out', 'coverage')
+var libPath = path.join(__dirname, '..', '..', 'lib')
+
+glob.sync('**/*.js', {cwd: libPath}).forEach(function (relativePath) {
+  var rawPath = path.join(libPath, relativePath)
+  var raw = fs.readFileSync(rawPath, 'utf8')
+
+  var generatedPath = path.join(outputPath, 'lib', relativePath)
+  var generated = instrumenter.instrumentSync(raw, rawPath)
+  mkdirp.sync(path.dirname(generatedPath))
+  fs.writeFileSync(generatedPath, generated)
+})
+
+var asarPath = path.join(outputPath, 'electron-instrumented.asar')
+asar.createPackageWithOptions(path.join(outputPath, 'lib'), asarPath, {}, function (error) {
+  if (error) {
+    console.error(error.stack || error)
+    process.exit(1)
+  }
+})