Respect always unlocked displays when keyguard is shown.

When keyguard is shown on the default display, all secondary displays
report mHasContent=false, even if these displays are created with
FLAG_ALWAYS_UNLOCKED (in practice this means that these displays
belong to an always unlocked virtual device).

Setting mHasContent=false on such displays is wrong - any windows
there are visible and interactive. This also does not propagate
display changes to these windows, which causes a bug when the display
is rotated.

Fix: 285141170
Test: m
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:1df55100cf2546c257b3722531a4668d193d3a1e)
Merged-In: Ief1fa2db10c234ba179ba741434ce3d6ebef290e
Change-Id: Ief1fa2db10c234ba179ba741434ce3d6ebef290e

services/core/java/com/android/server/wm/RootWindowContainer.java

diff --git a/services/core/java/com/android/server/wm/RootWindowContainer.java b/services/core/java/com/android/server/wm/RootWindowContainer.java
index 54fec3e..d9a954f 100644
--- a/services/core/java/com/android/server/wm/RootWindowContainer.java
+++ b/services/core/java/com/android/server/wm/RootWindowContainer.java
@@ -1061,8 +1061,10 @@
                 displayHasContent = true;
             } else if (displayContent != null &&
                     (!mObscureApplicationContentOnSecondaryDisplays
+                            || displayContent.isKeyguardAlwaysUnlocked()
                             || (obscured && type == TYPE_KEYGUARD_DIALOG))) {
-                // Allow full screen keyguard presentation dialogs to be seen.
+                // Allow full screen keyguard presentation dialogs to be seen, or simply ignore the
+                // keyguard if this display is always unlocked.
                 displayHasContent = true;
             }
             if ((privateflags & PRIVATE_FLAG_SUSTAINED_PERFORMANCE_MODE) != 0) {