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

mojo/edk/system/waiter.h

Index: mojo/edk/system/waiter.h
diff --git a/third_party/mojo/src/mojo/edk/system/waiter.h b/mojo/edk/system/waiter.h
similarity index 98%
copy from third_party/mojo/src/mojo/edk/system/waiter.h
copy to mojo/edk/system/waiter.h
index 945acbabd43120696fbc53ec7ebe069ed8f3afa4..8e983ec11335c7700f62005e77bf46efa735ebea 100644
--- a/third_party/mojo/src/mojo/edk/system/waiter.h
+++ b/mojo/edk/system/waiter.h
@@ -15,7 +15,7 @@
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
-namespace system {
+namespace edk {
 
 // IMPORTANT (all-caps gets your attention, right?): |Waiter| methods are called
 // under other locks, in particular, |Dispatcher::lock_|s, so |Waiter| methods
@@ -73,7 +73,7 @@ class MOJO_SYSTEM_IMPL_EXPORT Waiter final : public Awakable {
   MOJO_DISALLOW_COPY_AND_ASSIGN(Waiter);
 };
 
-}  // namespace system
+}  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_WAITER_H_