[hwc-batching] Surfaceflinger code for HWC batching support.

This CL adds the SurfaceFlinger side code for supporting the new
batched commands for createLayer/DestroyLayer.

Bug: 290685621
Test: atest VtsHalGraphicsComposer3_TargetTest
      atest PerInstance/GraphicsComposerAidlBatchedCommandTest
Change-Id: I1793bda0a1eac1c2cecd0c6ab00d5df9fd8d6d0a
diff --git a/services/surfaceflinger/common/FlagManager.cpp b/services/surfaceflinger/common/FlagManager.cpp
index 9b77751..cb1faee 100644
--- a/services/surfaceflinger/common/FlagManager.cpp
+++ b/services/surfaceflinger/common/FlagManager.cpp
@@ -127,7 +127,7 @@
     DUMP_READ_ONLY_FLAG(display_protected);
     DUMP_READ_ONLY_FLAG(fp16_client_target);
     DUMP_READ_ONLY_FLAG(game_default_frame_rate);
-
+    DUMP_READ_ONLY_FLAG(enable_layer_command_batching);
 #undef DUMP_READ_ONLY_FLAG
 #undef DUMP_SERVER_FLAG
 #undef DUMP_FLAG_INTERVAL
@@ -201,6 +201,7 @@
 FLAG_MANAGER_READ_ONLY_FLAG(display_protected, "")
 FLAG_MANAGER_READ_ONLY_FLAG(fp16_client_target, "debug.sf.fp16_client_target")
 FLAG_MANAGER_READ_ONLY_FLAG(game_default_frame_rate, "")
+FLAG_MANAGER_READ_ONLY_FLAG(enable_layer_command_batching, "")
 
 /// Trunk stable server flags ///
 FLAG_MANAGER_SERVER_FLAG(late_boot_misc2, "")