Switch WindowState to get display content from its window token

WindowState no longer needs to track what display it is on now
that the window token can only be on one display.

Test: Existing tests pass.
Change-Id: Ia0530d73da0b1ecc17f596ec62c933637bd1c2c3
diff --git a/services/core/java/com/android/server/wm/AppWindowToken.java b/services/core/java/com/android/server/wm/AppWindowToken.java
index 7e09c16..454b025 100644
--- a/services/core/java/com/android/server/wm/AppWindowToken.java
+++ b/services/core/java/com/android/server/wm/AppWindowToken.java
@@ -1184,16 +1184,16 @@
         }
     }
 
-    int rebuildWindowListUnchecked(DisplayContent dc, int addIndex) {
-        return super.rebuildWindowList(dc, addIndex);
+    int rebuildWindowListUnchecked(int addIndex) {
+        return super.rebuildWindowList(addIndex);
     }
 
     @Override
-    int rebuildWindowList(DisplayContent dc, int addIndex) {
+    int rebuildWindowList(int addIndex) {
         if (mIsExiting && !waitingForReplacement()) {
             return addIndex;
         }
-        return rebuildWindowListUnchecked(dc, addIndex);
+        return rebuildWindowListUnchecked(addIndex);
     }
 
     @Override