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

content/child/BUILD.gn

Index: content/child/BUILD.gn
diff --git a/content/child/BUILD.gn b/content/child/BUILD.gn
index 0d13f5d99ff675e20aa04ab3a76dc9e88ba27a48..b61403e2c3bb986c512b02cabfea30f89df6d137 100644
--- a/content/child/BUILD.gn
+++ b/content/child/BUILD.gn
@@ -18,9 +18,13 @@ source_set("child") {
 
   configs += [ "//build/config:precompiled_headers" ]
 
-  public_deps = [
-    "//third_party/mojo/src/mojo/edk/system",
-  ]
+  public_deps = []
+
+  if (use_chrome_edk) {
+    public_deps += [ "//mojo/edk/system" ]
+  } else {
+    public_deps += [ "//third_party/mojo/src/mojo/edk/system" ]
+  }
 
   deps = [
     "//base",