Don't set up external displays from binder thread

This fixes a bug where keyguard was attempting to set up
external presentation displays from the binder thread instead
of the UI thread.  Bad dog.

Fixes bug 11676486

Change-Id: Iadbe485691acc56a41b23219fe399f7eda40cb7c

packages/Keyguard/src/com/android/keyguard/KeyguardViewMediator.java

@@ -614,7 +614,14 @@ public class KeyguardViewMediator {
             }
         }
         KeyguardUpdateMonitor.getInstance(mContext).dispatchScreenTurndOff(why);
-        mKeyguardDisplayManager.show();
+
+        // This needs to run on the UI thread
+        mHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                mKeyguardDisplayManager.show();
+            }
+        });
     }
 
     private void doKeyguardLaterLocked() {