Don't log BlockGuard violations on ENG builds.

We want to see CloseGuard violations in the log in ENG builds
because they indicate serious problems, but BlockGuard is
too noisy and is best viewed in the aggregate from the
drop box based tools.

Change-Id: I77d4d0a561a4299355c111d0ccb5a2147646245b

Author: Jeff Brown

core/java/android/os/StrictMode.java

@@ -35,7 +35,6 @@
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -902,22 +901,22 @@ public static boolean conditionallyEnableDebugLogging() {
             return false;
         }
 
+        // Thread policy controls BlockGuard.
         int threadPolicyMask = StrictMode.DETECT_DISK_WRITE |
                 StrictMode.DETECT_DISK_READ |
                 StrictMode.DETECT_NETWORK;
 
         if (!IS_USER_BUILD) {
             threadPolicyMask |= StrictMode.PENALTY_DROPBOX;
-            if (IS_ENG_BUILD) {
-                threadPolicyMask |= StrictMode.PENALTY_LOG;
-            }
         }
         if (doFlashes) {
             threadPolicyMask |= StrictMode.PENALTY_FLASH;
         }
 
         StrictMode.setThreadPolicyMask(threadPolicyMask);
 
+        // VM Policy controls CloseGuard, detection of Activity leaks,
+        // and instance counting.
         if (IS_USER_BUILD) {
             setCloseGuardEnabled(false);
         } else {