add flag to switch to SkTextEncoding

Bug: skia:2664
Change-Id: I3a565b6dd47e9e09deaadb7e0962d95420fe8935
Reviewed-on: https://chromium-review.googlesource.com/c/1358692Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613103}

skia/config/SkUserConfig.h

@@ -157,6 +157,10 @@ SK_API void SkDebugf_FileLine(const char* file, int line, bool fatal,
 #define SK_DISABLE_EXPLICIT_GPU_RESOURCE_ALLOCATION
 #endif
 
+#ifndef SK_SUPPORT_LEGACY_TEXTENCODINGENUM
+#define SK_SUPPORT_LEGACY_TEXTENCODINGENUM
+#endif
+
 #ifndef SK_IGNORE_LINEONLY_AA_CONVEX_PATH_OPTS
 #define SK_IGNORE_LINEONLY_AA_CONVEX_PATH_OPTS
 #endif