Handle the case where null is returned for USB_STATE intent.

USB_STATE is not received if USB_STATE has not changed from
the initial state. This CL adds handling for that case.

BUG: 22163689
Change-Id: I232a558caaac4f4984f7629e2574d478fc7ad432

src/com/android/settings/deviceinfo/UsbBackend.java

@@ -47,7 +47,8 @@ public class UsbBackend {
     public UsbBackend(Context context) {
         Intent intent = context.registerReceiver(null,
                 new IntentFilter(UsbManager.ACTION_USB_STATE));
-        mIsUnlocked = intent.getBooleanExtra(UsbManager.USB_DATA_UNLOCKED, false);
+        mIsUnlocked = intent == null ?
+                false : intent.getBooleanExtra(UsbManager.USB_DATA_UNLOCKED, false);
 
         mUserManager = UserManager.get(context);
         mUsbManager = context.getSystemService(UsbManager.class);
@@ -151,4 +152,4 @@ public class UsbBackend {
         // No port, support sink modes only.
         return (mode & MODE_POWER_MASK) != MODE_POWER_SOURCE;
     }
-}
+}