Flag: Add flag for cursor plane behavior

This change adds a flag which is used to gate behavior changes to the
cursor surface that allows it to be presented on the cursor plane.

In subsequent CLs, when the cursor_plane_compatibility flag is set,
Sprite surfaces will use BGRA pixel format, and will allocate buffers
with the GRALLOC_USAGE_CURSOR flag. These modifications enable the
requirements of the cursor plane to be met.

Flag: com.android.graphics.libgui.flags.cursor_plane_compatibility
Bug: 404877772
Change-Id: I0eee89a99f340af642fcf1de187f6e550ce99527

Author: Andrew Wolfers

libs/gui/Android.bp

@@ -349,6 +349,10 @@ cc_library_shared {
         "libsurfaceflingerflags",
     ],
 
+    shared_libs: [
+       "libaconfig_storage_read_api_cc",
+    ],
+
     afdo: true,
 
     lto: {

libs/gui/libgui_flags.aconfig

@@ -25,6 +25,13 @@ flag {
   is_fixed_read_only: true
 } # bq_consumer_attach_callback
 
+flag {
+  name: "cursor_plane_compatibility"
+  namespace: "desktop_display"
+  description: "configure cursor surface to meet cursor plane buffer requirements"
+  bug: "352067404"
+} # cursor_plane_compatibility
+
 flag {
   name: "frametimestamps_previousrelease"
   namespace: "core_graphics"