Prevent windows below the keyguard from showing

Fixes a bug where windows below the lock screen
could become visible if a SHOW_WHEN_LOCKED activity
hides the status bar.

Bug: 21450145
Change-Id: Ie660394cb96d7e6839bd4fb7c2729133bac2dfc5
diff --git a/services/core/java/com/android/server/policy/PhoneWindowManager.java b/services/core/java/com/android/server/policy/PhoneWindowManager.java
index b8d0692..2839f08 100644
--- a/services/core/java/com/android/server/policy/PhoneWindowManager.java
+++ b/services/core/java/com/android/server/policy/PhoneWindowManager.java
@@ -2116,7 +2116,9 @@
             case TYPE_KEYGUARD_SCRIM:
                 return false;
             default:
-                return true;
+                // Hide only windows below the keyguard host window.
+                return windowTypeToLayerLw(win.getBaseType())
+                        < windowTypeToLayerLw(TYPE_STATUS_BAR);
         }
     }
 
@@ -5517,6 +5519,12 @@
 
     /** {@inheritDoc} */
     @Override
+    public boolean isKeyguardShowingOrOccluded() {
+        return mKeyguardDelegate == null ? false : mKeyguardDelegate.isShowing();
+    }
+
+    /** {@inheritDoc} */
+    @Override
     public boolean inKeyguardRestrictedKeyInputMode() {
         if (mKeyguardDelegate == null) return false;
         return mKeyguardDelegate.isInputRestricted();