While running the Robocop test "TEST_PATH=testLoad make mochitest-robotium", I saw the following NFC exception logged (but no crash). I'm running Android 4.2. https://github.com/android/platform_frameworks_base/blob/2c10311a01a9414a8efcedb267a45289a1617888/core/java/android/nfc/NfcActivityManager.java#L115 E/NFC (30166): Cannot call API with Activity that has already been destroyed E/NFC (30166): java.lang.IllegalStateException: activity is already destroyed E/NFC (30166): at android.nfc.NfcActivityManager$NfcActivityState.<init>(NfcActivityManager.java:115) E/NFC (30166): at android.nfc.NfcActivityManager.getActivityState(NfcActivityManager.java:162) E/NFC (30166): at android.nfc.NfcActivityManager.setNdefPushMessageCallback(NfcActivityManager.java:234) E/NFC (30166): at android.nfc.NfcAdapter.setNdefPushMessageCallback(NfcAdapter.java:896) E/NFC (30166): at org.mozilla.gecko.BrowserApp.onDestroy(BrowserApp.java:543) E/NFC (30166): at android.app.Activity.performDestroy(Activity.java:5273) E/NFC (30166): at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1110) E/NFC (30166): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3565) E/NFC (30166): at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3596) E/NFC (30166): at android.app.ActivityThread.access$1200(ActivityThread.java:153) E/NFC (30166): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1300) E/NFC (30166): at android.os.Handler.dispatchMessage(Handler.java:99) E/NFC (30166): at android.os.Looper.loop(Looper.java:137) E/NFC (30166): at android.app.ActivityThread.main(ActivityThread.java:5226) E/NFC (30166): at java.lang.reflect.Method.invokeNative(Native Method) E/NFC (30166): at java.lang.reflect.Method.invoke(Method.java:511) E/NFC (30166): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795) E/NFC (30166): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562) E/NFC (30166): at dalvik.system.NativeStart.main(Native Method)

Brian fixed this as part of bug 851056.

Marking fixed; reopen if it isn't gone.