Add window extensions to AOSP cuttlefish foldable target.

Bug: 213619277
Change-Id: I2a4295e0d7300114bf8a7df1cb566788ebe60d9d
diff --git a/vsoc_x86_64/phone/aosp_cf_foldable.mk b/vsoc_x86_64/phone/aosp_cf_foldable.mk
index 99f8f4a..c0872d8 100644
--- a/vsoc_x86_64/phone/aosp_cf_foldable.mk
+++ b/vsoc_x86_64/phone/aosp_cf_foldable.mk
@@ -25,6 +25,11 @@
     device/google/cuttlefish/shared/foldable/display_layout_configuration.xml:$(TARGET_COPY_OUT_VENDOR)/etc/displayconfig/display_layout_configuration.xml \
     device/google/cuttlefish/shared/foldable/display_settings.xml:$(TARGET_COPY_OUT_VENDOR)/etc/display_settings.xml \
 
+# Sidecar and window extensions enhance multi-display, tablet, and foldable support.
+PRODUCT_PACKAGES += \
+    androidx.window.extensions \
+    androidx.window.sidecar \
+
 # Include RRO settings that specify the fold states and screen information.
 DEVICE_PACKAGE_OVERLAYS += device/google/cuttlefish/shared/foldable/overlay
 # Include the foldable `launch_cvd --config foldable` option.