Initial work on Dart bindings for Mojo.

mojo/public/BUILD.gn

Index: mojo/public/BUILD.gn
diff --git a/mojo/public/BUILD.gn b/mojo/public/BUILD.gn
index 35619fa98bb95b41a461aa92d7249038174b7859..6757105efc4b66ee602a55a54a4d078e0b543f6b 100644
--- a/mojo/public/BUILD.gn
+++ b/mojo/public/BUILD.gn
@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//mojo/public/mojo.gni")
+
 group("public") {
   # Meta-target, don't link into production code.
   testonly = true
@@ -22,6 +24,12 @@ group("public") {
     ]
   }
 
+  if (mojo_use_dart) {
+    deps += [
+      "//mojo/public/dart",
+    ]
+  }
+
   if (is_android) {
     deps += [
       "//mojo/public/java:system",