Fix doc for FLAG_DISMISS_KEYGUARD

Test: n/a
Change-Id: I7e8b0e22895e5efe839dc0f73bcfda6a67f52026
Fix: 36023803
diff --git a/core/java/android/view/WindowManager.java b/core/java/android/view/WindowManager.java
index 666ccf4..8445b37 100644
--- a/core/java/android/view/WindowManager.java
+++ b/core/java/android/view/WindowManager.java
@@ -978,8 +978,9 @@
          * seeing this window, unless {@link #FLAG_SHOW_WHEN_LOCKED} has
          * also been set.
          * @deprecated Use {@link #FLAG_SHOW_WHEN_LOCKED} or {@link KeyguardManager#dismissKeyguard}
-         * instead. The Keyguard should never be dismissed automatically repeatedly as it also
-         * guards against unintentional touches.
+         * instead. Since keyguard was dismissed all the time as long as an activity with this flag
+         * on its window was focused, keyguard couldn't guard against unintentional touches on the
+         * screen, which isn't desired.
          */
         @Deprecated
         public static final int FLAG_DISMISS_KEYGUARD = 0x00400000;