Camera: Add per-surface mirroring mode

Add the support to do per output surface mirror mode. Previously
mirroring mode is set per OutputConfiguration, which could contain
multiple shared surfaces.

Flag: com.android.internal.camera.flags.mirror_mode_shared_surfaces
Test: atest MultiViewTest
Bug: 298899993
Change-Id: I3654cb585d243365b62a10131c21a869af754e73
diff --git a/camera/camera_platform.aconfig b/camera/camera_platform.aconfig
index 8e53ca0..cabfbc4 100644
--- a/camera/camera_platform.aconfig
+++ b/camera/camera_platform.aconfig
@@ -178,3 +178,11 @@
     description: "Pass the full AttributionSource chain to PermissionChecker"
     bug: "190657833"
 }
+
+flag {
+    namespace: "camera_platform"
+    name: "mirror_mode_shared_surfaces"
+    is_exported: true
+    description: "Support setting and getting mirror mode for shared surfaces"
+    bug: "298899993"
+}