Add devtool property for webpack

- Use inline-source-map for karma-webpack

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin
 import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
 import org.jetbrains.kotlin.gradle.targets.js.testing.*
 import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpackConfig
+import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpackConfig.Devtool
 import org.jetbrains.kotlin.gradle.testing.internal.reportsDir
 import org.slf4j.Logger
 import java.io.File
@@ -252,6 +253,7 @@ class KotlinKarma(override val compilation: KotlinJsCompilation) : KotlinJsTestF
         val webpackConfigWriter = KotlinWebpackConfig(
             configDirectory = project.projectDir.resolve("webpack.config.d").takeIf { it.isDirectory },
             sourceMaps = true,
+            devtool = Devtool.INLINE_SOURCE_MAP,
             export = false,
             progressReporter = true,
             progressReporterPathFilter = nodeJs.rootPackageDir.absolutePath

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpackConfig.kt

@@ -25,7 +25,8 @@ data class KotlinWebpackConfig(
     val configDirectory: File? = null,
     val bundleAnalyzerReportDir: File? = null,
     val reportEvaluatedConfigFile: File? = null,
-    var devServer: DevServer? = null,
+    val devServer: DevServer? = null,
+    val devtool: Devtool = Devtool.EVAL_SOURCE_MAP,
     val showProgress: Boolean = false,
     val sourceMaps: Boolean = false,
     val export: Boolean = true,
@@ -75,6 +76,12 @@ data class KotlinWebpackConfig(
         val contentBase: List<String>
     ) : Serializable
 
+    enum class Devtool(val code: String) {
+        EVAL_SOURCE_MAP("eval-source-map"),
+        SOURCE_MAP("source-map"),
+        INLINE_SOURCE_MAP("inline-source-map")
+    }
+
     fun save(configFile: File) {
         configFile.writer().use {
             appendTo(it)
@@ -173,7 +180,7 @@ data class KotlinWebpackConfig(
         if (devServer == null) return
 
         appendln("// dev server")
-        appendln("config.devServer = ${json(devServer!!)};")
+        appendln("config.devServer = ${json(devServer)};")
         appendln()
     }
 
@@ -189,7 +196,7 @@ data class KotlinWebpackConfig(
                         use: ["source-map-loader"],
                         enforce: "pre"
                 });
-                config.devtool = 'eval-source-map';
+                config.devtool = '${devtool.code}';
                 
             """.trimIndent()
         )