avoid use of java.lang.management.ManagementFactory

Author: nbransby

src/main/java/android/os/SystemClock.java

@@ -1,12 +1,14 @@
 package android.os;
 
-import java.lang.management.ManagementFactory;
 
 public final class SystemClock {
+
+    private static final long startTime = System.currentTimeMillis();
+
     public static long elapsedRealtime() {
-        return ManagementFactory.getRuntimeMXBean().getUptime();
+        return System.currentTimeMillis() - startTime;
     }
     public static long uptimeMillis() {
-        return ManagementFactory.getRuntimeMXBean().getUptime();
+        return System.currentTimeMillis() - startTime;
     }
 }