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

mojo/edk/system/process_identifier.h

Index: mojo/edk/system/process_identifier.h
diff --git a/third_party/mojo/src/mojo/edk/system/process_identifier.h b/mojo/edk/system/process_identifier.h
similarity index 69%
copy from third_party/mojo/src/mojo/edk/system/process_identifier.h
copy to mojo/edk/system/process_identifier.h
index dd1157a795a40dc60bc81b5950106ecf11b54b58..91ee9728490e7f7201825bb81596674332a65b0e 100644
--- a/third_party/mojo/src/mojo/edk/system/process_identifier.h
+++ b/mojo/edk/system/process_identifier.h
@@ -2,13 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef THIRD_PARTY_MOJO_SRC_MOJO_EDK_SYSTEM_PROCESS_IDENTIFIER_H_
-#define THIRD_PARTY_MOJO_SRC_MOJO_EDK_SYSTEM_PROCESS_IDENTIFIER_H_
+#ifndef MOJO_EDK_SYSTEM_PROCESS_IDENTIFIER_H_
+#define MOJO_EDK_SYSTEM_PROCESS_IDENTIFIER_H_
 
 #include <stdint.h>
 
 namespace mojo {
-namespace system {
+namespace edk {
 
 // Identifiers for processes (note that these are not OS process IDs):
 using ProcessIdentifier = uint64_t;
@@ -19,7 +19,7 @@ const ProcessIdentifier kInvalidProcessIdentifier = 0;
 // The master process will always have this process identifier.
 const ProcessIdentifier kMasterProcessIdentifier = 1;
 
-}  // namespace system
+}  // namespace edk
 }  // namespace mojo
 
-#endif  // THIRD_PARTY_MOJO_SRC_MOJO_EDK_SYSTEM_PROCESS_IDENTIFIER_H_
+#endif  // MOJO_EDK_SYSTEM_PROCESS_IDENTIFIER_H_