Build sky/engine/tonic

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 3044654e15b6f5e8e4fe5ece375e32ef0200d45d..d23d33e122fd88014173ae83a2278abed504f723 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -11,7 +11,6 @@ group("default") {
     "//mojo",
     "//services",
     "//shell",
-    "//sky",
     "//ui/gfx:gfx_unittests",
     "//ui/events:events_unittests",
   ]
@@ -19,6 +18,10 @@ group("default") {
   if (!is_android && !is_win) {
     deps += [ "//tools/xdisplaycheck" ]
   }
+
+  if (!is_asan) {
+    deps += [ "//sky" ]
+  }
 }
 
 # Deprecated name for the default build target.