Restore session params "no decoration" flag

This seems to have removed from a previous version and the theme editor
relies on it to remove the decoration around the preview.

Change-Id: Ifab99e9c1689bfe44ca593e8c66c24e57c3e8c4c

Author: diegopl

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/impl/Layout.java

@@ -329,9 +329,12 @@ public Builder(@NonNull SessionParams params, @NonNull BridgeContext context) {
             mWindowIsFloating = getBooleanThemeValue(mResources, ATTR_WINDOW_FLOATING, true, true);
 
             findBackground();
-            findStatusBar();
-            findActionBar();
-            findNavBar();
+
+            if (!mParams.isForceNoDecor()) {
+                findStatusBar();
+                findActionBar();
+                findNavBar();
+            }
         }
 
         private void findBackground() {