Add SK_SUPPORT_LEGACY_AAA_CHOICE

For https://skia-review.googlesource.com/c/skia/+/144412

Change-Id: I9c1f983bb7020a3335bf58739cdaf343a7f983db
Reviewed-on: https://chromium-review.googlesource.com/1157516Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579795}

skia/config/SkUserConfig.h

@@ -193,6 +193,10 @@ SK_API void SkDebugf_FileLine(const char* file, int line, bool fatal,
 #define SK_SUPPORT_LEGACY_VULKAN_INTERFACE
 #endif
 
+#ifndef SK_SUPPORT_LEGACY_AAA_CHOICE
+#define SK_SUPPORT_LEGACY_AAA_CHOICE
+#endif
+
 ///////////////////////// Imported from BUILD.gn and skia_common.gypi
 
 /* In some places Skia can use static initializers for global initialization,