Remove scalajs-fake-insecure-java-securerandom dependency (#465)

* Remove fake insecure random dependency

* Re-implement randomUUID() on Scala.js

build.sbt

@@ -119,16 +119,6 @@ lazy val runtime = CrossProject(
   .jvmSettings(
     Test / fork := true
   )
-  .jsSettings(
-    scalaJSStage := FastOptStage,
-    // While not exactlu ideal, this is only used in the invoker to assign a
-    // unique id to ensure measurements have unique ids. It's never exposed to
-    // the user and doesn't touch anything sensitve, so we should have no
-    // issues here. Still, I don't like having this, so we should try to
-    // replace it.
-    libraryDependencies += ("org.scala-js" %%% "scalajs-fake-insecure-java-securerandom" % "1.0.0")
-      .cross(CrossVersion.for3Use2_13)
-  )
 
 lazy val `runtimeJVM` = runtime.jvm
 lazy val `runtimeJS` = runtime.js

runtime/js/src/main/scala/scoverage/Platform.scala

@@ -17,4 +17,15 @@ object Platform {
 
   lazy val Source = SupportSource
 
+  def insecureRandomUUID() = {
+    import scala.util.Random
+    var msb = Random.nextLong()
+    var lsb = Random.nextLong()
+    msb &= 0xffffffffffff0fffL // clear version
+    msb |= 0x0000000000004000L // set to version 4
+    lsb &= 0x3fffffffffffffffL // clear variant
+    lsb |= 0x8000000000000000L // set to IETF variant
+    new java.util.UUID(msb, lsb)
+  }
+
 }

runtime/jvm/src/main/scala/scoverage/Platform.scala

@@ -16,4 +16,7 @@ object Platform {
   type FileFilter = SupportFileFilter
 
   lazy val Source = SupportSource
+
+  def insecureRandomUUID() = java.util.UUID.randomUUID()
+
 }

runtime/shared/src/main/scala/scoverage/Invoker.scala

@@ -8,7 +8,7 @@ import scoverage.Platform._
 /** @author Stephen Samuel */
 object Invoker {
 
-  private val runtimeUUID = java.util.UUID.randomUUID()
+  private val runtimeUUID = Platform.insecureRandomUUID()
 
   private val MeasurementsPrefix = "scoverage.measurements."
   private val threadFiles = new ThreadLocal[mutable.HashMap[String, FileWriter]]