Add a Mojo EDK for Chrome that uses one OS pipe per message pipe.

third_party/mojo/src/mojo/public/c/system/BUILD.gn

Index: third_party/mojo/src/mojo/public/c/system/BUILD.gn
diff --git a/third_party/mojo/src/mojo/public/c/system/BUILD.gn b/third_party/mojo/src/mojo/public/c/system/BUILD.gn
index 6a3827c054f5706ced624506d2e31e8e7a9de516..6f797b3bbbfa0ceef3595e071e8d21e8cc3219df 100644
--- a/third_party/mojo/src/mojo/public/c/system/BUILD.gn
+++ b/third_party/mojo/src/mojo/public/c/system/BUILD.gn
@@ -48,8 +48,10 @@ group("for_component") {
     ":system",
   ]
   if (is_component_build) {
-    deps = [
-      "../../../edk/system",
-    ]
+    if (use_chrome_edk) {
+      deps += [ "//mojo/edk/system" ]
+    } else {
+      deps += [ "//third_party/mojo/src/mojo/edk/system" ]
+    }
   }
 }