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

mojo/edk/system/shared_buffer_dispatcher.h

Index: mojo/edk/system/shared_buffer_dispatcher.h
diff --git a/third_party/mojo/src/mojo/edk/system/shared_buffer_dispatcher.h b/mojo/edk/system/shared_buffer_dispatcher.h
similarity index 93%
copy from third_party/mojo/src/mojo/edk/system/shared_buffer_dispatcher.h
copy to mojo/edk/system/shared_buffer_dispatcher.h
index 1222e030c185364ce3347b229a2bdcaa9c230141..bd8ef260a28ba16ba5fa562482f2398141c04071 100644
--- a/third_party/mojo/src/mojo/edk/system/shared_buffer_dispatcher.h
+++ b/mojo/edk/system/shared_buffer_dispatcher.h
@@ -55,7 +55,6 @@ class MOJO_SYSTEM_IMPL_EXPORT SharedBufferDispatcher final
   // The "opposite" of |SerializeAndClose()|. (Typically this is called by
   // |Dispatcher::Deserialize()|.)
   static scoped_refptr<SharedBufferDispatcher> Deserialize(
-      Channel* channel,
       const void* source,
       size_t size,
       embedder::PlatformHandleVector* platform_handles);
@@ -91,19 +90,14 @@ class MOJO_SYSTEM_IMPL_EXPORT SharedBufferDispatcher final
       uint64_t num_bytes,
       MojoMapBufferFlags flags,
       scoped_ptr<embedder::PlatformSharedBufferMapping>* mapping) override;
-  void StartSerializeImplNoLock(Channel* channel,
-                                size_t* max_size,
-                                size_t* max_platform_handles) override
-      MOJO_NOT_THREAD_SAFE;
+  void StartSerializeImplNoLock(size_t* max_size,
+                                size_t* max_platform_handles) override;
   bool EndSerializeAndCloseImplNoLock(
-      Channel* channel,
       void* destination,
       size_t* actual_size,
-      embedder::PlatformHandleVector* platform_handles) override
-      MOJO_NOT_THREAD_SAFE;
+      embedder::PlatformHandleVector* platform_handles) override;
 
-  scoped_refptr<embedder::PlatformSharedBuffer> shared_buffer_
-      MOJO_GUARDED_BY(mutex());
+  scoped_refptr<embedder::PlatformSharedBuffer> shared_buffer_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(SharedBufferDispatcher);
 };