Allow some app windows to display above the IME.

- Display child windows of the current IME target above the IME.
- Display app windows above the current IME target above the IME.

Regression in the functionality was introduce in
I6f8bf15ba246fac69c4a496ebb1d9e0b9b6a95a2 when we switch away from using
the window list for z-ordering and using the hierarchy which has the IME
above all app windows.

Change-Id: I399aab7fd5ad7327ef6bc29d48f6d9bf48a6ac6c
Fixes: 33128382
Test: bit FrameworksServicesTests:com.android.server.wm.WindowLayersControllerTests
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index e73acde..18568ba4 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -141,8 +141,6 @@
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.function.Consumer;
-import java.util.function.Function;
 
 /**
  * Utility class for keeping track of the WindowStates and other pertinent contents of a
@@ -2546,7 +2544,7 @@
             if (!obscured) {
                 final boolean isDisplayed = w.isDisplayedLw();
 
-                if (isDisplayed && w.isObscuringFullscreen(mDisplayInfo)) {
+                if (isDisplayed && w.isObscuringDisplay()) {
                     // This window completely covers everything behind it, so we want to leave all
                     // of them as undimmed (for performance reasons).
                     root.mObscuringWindow = w;
@@ -2945,7 +2943,7 @@
                     screenshotReady = true;
                 }
 
-                if (ws.isObscuringFullscreen(mDisplayInfo)){
+                if (ws.isObscuringDisplay()){
                     break;
                 }
             }