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

mojo/edk/system/handle_signals_state.h

Index: mojo/edk/system/handle_signals_state.h
diff --git a/third_party/mojo/src/mojo/edk/system/handle_signals_state.h b/mojo/edk/system/handle_signals_state.h
similarity index 97%
copy from third_party/mojo/src/mojo/edk/system/handle_signals_state.h
copy to mojo/edk/system/handle_signals_state.h
index 78a3d65529edbea9679809152f2b7f801a5494f9..1c47a288c1e27914798e2f8395f2122b873a5172 100644
--- a/third_party/mojo/src/mojo/edk/system/handle_signals_state.h
+++ b/mojo/edk/system/handle_signals_state.h
@@ -9,7 +9,7 @@
 #include "mojo/public/c/system/types.h"
 
 namespace mojo {
-namespace system {
+namespace edk {
 
 // Just "add" some constructors and methods to the C struct
 // |MojoHandleSignalsState| (for convenience). This should add no overhead.
@@ -43,7 +43,7 @@ struct MOJO_SYSTEM_IMPL_EXPORT HandleSignalsState final
 static_assert(sizeof(HandleSignalsState) == sizeof(MojoHandleSignalsState),
               "HandleSignalsState should add no overhead");
 
-}  // namespace system
+}  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_HANDLE_SIGNALS_STATE_H_