Reland "Don't enable jdwp by default on userdebug builds""

This reverts commit 50c258ca37.

Reason for revert: Relanding after fixes for the failures Fixes:
1. Mark the com.android.perftests.core as profileable from shell so
that we would be able to read /proc/self/io
2. Fix a JDWP test to expect the new behaviour on userdebug builds.
We can no longer attach debugger on profileable apps on userdebug builds

Bug: 240410400, 246616689
Test: System boots
Change-Id: I6fff6f1a683893244bc2d40f930044747befb2ce

apct-tests/perftests/core/AndroidManifest.xml

@@ -15,6 +15,7 @@
 
     <application>
         <uses-library android:name="android.test.runner" />
+        <profileable android:shell="true" />
         <activity android:name="android.perftests.utils.PerfTestActivity"
             android:exported="true">
           <intent-filter>

core/java/com/android/internal/os/Zygote.java

@@ -1000,17 +1000,25 @@ public final class Zygote {
         }
     }
 
+    /**
+     * This will enable jdwp by default for all apps. It is OK to cache this property
+     * because we expect to reboot the system whenever this property changes
+     */
+    private static final boolean ENABLE_JDWP = SystemProperties.get(
+                          "persist.debug.dalvik.vm.jdwp.enabled").equals("1");
+
     /**
      * Applies debugger system properties to the zygote arguments.
      *
-     * If "ro.debuggable" is "1", all apps are debuggable. Otherwise,
-     * the debugger state is specified via the "--enable-jdwp" flag
-     * in the spawn request.
+     * For eng builds all apps are debuggable. On userdebug and user builds
+     * if persist.debuggable.dalvik.vm.jdwp.enabled is 1 all apps are
+     * debuggable. Otherwise, the debugger state is specified via the
+     * "--enable-jdwp" flag in the spawn request.
      *
      * @param args non-null; zygote spawner args
      */
     static void applyDebuggerSystemProperty(ZygoteArguments args) {
-        if (RoSystemProperties.DEBUGGABLE) {
+        if (Build.IS_ENG || ENABLE_JDWP) {
             args.mRuntimeFlags |= Zygote.DEBUG_ENABLE_JDWP;
         }
     }