[canvaskit] Speculative fix for external wasm library

See https://groups.google.com/forum/#!topic/skia-discuss/J2XT7XjmFtI

Change-Id: I4daabc160e9f5b09d4233bcaf24661c8473c0d07
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/246080
Reviewed-by: Ben Wagner <bungeman@google.com>
diff --git a/tools/embed_resources.py b/tools/embed_resources.py
index 5e8d0e4..675a9fe 100644
--- a/tools/embed_resources.py
+++ b/tools/embed_resources.py
@@ -39,7 +39,8 @@
   args = parser.parse_args()
 
   out = args.output.write;
-  out('#include "include/core/SkTypes.h"\n')
+  out('#include <stddef.h>\n')
+  out('#include <stdint.h>\n')
 
   # Write the resources.
   index = 0