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

mojo/edk/system/mapping_table.h

Index: mojo/edk/system/mapping_table.h
diff --git a/third_party/mojo/src/mojo/edk/system/mapping_table.h b/mojo/edk/system/mapping_table.h
similarity index 86%
copy from third_party/mojo/src/mojo/edk/system/mapping_table.h
copy to mojo/edk/system/mapping_table.h
index 5af16557c24d7d0d6b97a65ee88a6a23a0e19da6..ce416e12ce88661e726da36c2ba0339f8b29ac3a 100644
--- a/third_party/mojo/src/mojo/edk/system/mapping_table.h
+++ b/mojo/edk/system/mapping_table.h
@@ -17,13 +17,9 @@
 
 namespace mojo {
 
-namespace embedder {
-class PlatformSharedBufferMapping;
-}
-
-namespace system {
-
+namespace edk {
 class Core;
+class PlatformSharedBufferMapping;
 
 // Test-only function (defined/used in embedder/test_embedder.cc). Declared here
 // so it can be friended.
@@ -42,21 +38,20 @@ class MOJO_SYSTEM_IMPL_EXPORT MappingTable {
 
   // Tries to add a mapping. (Takes ownership of the mapping in all cases; on
   // failure, it will be destroyed.)
-  MojoResult AddMapping(
-      scoped_ptr<embedder::PlatformSharedBufferMapping> mapping);
+  MojoResult AddMapping(scoped_ptr<PlatformSharedBufferMapping> mapping);
   MojoResult RemoveMapping(uintptr_t address);
 
  private:
   friend bool internal::ShutdownCheckNoLeaks(Core*);
 
   using AddressToMappingMap =
-      base::hash_map<uintptr_t, embedder::PlatformSharedBufferMapping*>;
+      base::hash_map<uintptr_t, PlatformSharedBufferMapping*>;
   AddressToMappingMap address_to_mapping_map_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(MappingTable);
 };
 
-}  // namespace system
+}  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MAPPING_TABLE_H_