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

mojo/edk/js/waiting_callback.h

Index: mojo/edk/js/waiting_callback.h
diff --git a/third_party/mojo/src/mojo/edk/js/waiting_callback.h b/mojo/edk/js/waiting_callback.h
similarity index 98%
copy from third_party/mojo/src/mojo/edk/js/waiting_callback.h
copy to mojo/edk/js/waiting_callback.h
index 5a9dfaffa884cbbb26f83c2a9bdb0cfe09b05edf..c1b76aaf47e6afc2bf6e330d8f348d6534286548 100644
--- a/third_party/mojo/src/mojo/edk/js/waiting_callback.h
+++ b/mojo/edk/js/waiting_callback.h
@@ -15,7 +15,7 @@
 #include "mojo/public/cpp/system/core.h"
 
 namespace mojo {
-namespace js {
+namespace edk {
 
 class WaitingCallback : public gin::Wrappable<WaitingCallback>,
                         public HandleCloseObserver {
@@ -62,7 +62,7 @@ class WaitingCallback : public gin::Wrappable<WaitingCallback>,
   DISALLOW_COPY_AND_ASSIGN(WaitingCallback);
 };
 
-}  // namespace js
+}  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_JS_WAITING_CALLBACK_H_