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

ipc/mojo/ipc_channel_mojo.h

Index: ipc/mojo/ipc_channel_mojo.h
diff --git a/ipc/mojo/ipc_channel_mojo.h b/ipc/mojo/ipc_channel_mojo.h
index e7b7b767a68a5a82d20fea25ad0a92121b3dffe5..e051c92e363175a7b8a49987b2652460cf362860 100644
--- a/ipc/mojo/ipc_channel_mojo.h
+++ b/ipc/mojo/ipc_channel_mojo.h
@@ -17,9 +17,12 @@
 #include "ipc/mojo/ipc_message_pipe_reader.h"
 #include "ipc/mojo/ipc_mojo_bootstrap.h"
 #include "ipc/mojo/scoped_ipc_support.h"
-#include "third_party/mojo/src/mojo/edk/embedder/channel_info_forward.h"
 #include "third_party/mojo/src/mojo/public/cpp/system/core.h"
 
+#if !defined(USE_CHROME_EDK)
+#include "third_party/mojo/src/mojo/edk/embedder/channel_info_forward.h"
+#endif
+
 namespace IPC {
 
 // Mojo-based IPC::Channel implementation over a platform handle.
@@ -53,9 +56,11 @@ class IPC_MOJO_EXPORT ChannelMojo
  public:
   using CreateMessagingPipeCallback =
       base::Callback<void(mojo::ScopedMessagePipeHandle)>;
+#if !defined(USE_CHROME_EDK)
   using CreateMessagingPipeOnIOThreadCallback =
       base::Callback<void(mojo::ScopedMessagePipeHandle,
                           mojo::embedder::ChannelInfo*)>;
+#endif
 
   // True if ChannelMojo should be used regardless of the flag.
   static bool ShouldBeUsed();
@@ -128,15 +133,20 @@ class IPC_MOJO_EXPORT ChannelMojo
               Mode mode,
               Listener* listener,
               AttachmentBroker* broker);
-
+#if defined(USE_CHROME_EDK)
+  void CreateMessagingPipe(mojo::edk::ScopedPlatformHandle handle,
+                           const CreateMessagingPipeCallback& callback);
+#else
   void CreateMessagingPipe(mojo::embedder::ScopedPlatformHandle handle,
                            const CreateMessagingPipeCallback& callback);
+#endif
   void InitMessageReader(mojo::ScopedMessagePipeHandle pipe, int32_t peer_pid);
 
   Listener* listener() const { return listener_; }
   void set_peer_pid(base::ProcessId pid) { peer_pid_ = pid; }
 
  private:
+#if !defined(USE_CHROME_EDK)
   struct ChannelInfoDeleter {
     explicit ChannelInfoDeleter(scoped_refptr<base::TaskRunner> io_runner);
     ~ChannelInfoDeleter();
@@ -145,6 +155,7 @@ class IPC_MOJO_EXPORT ChannelMojo
 
     scoped_refptr<base::TaskRunner> io_runner;
   };
+#endif
 
   // ChannelMojo needs to kill its MessagePipeReader in delayed manner
   // because the channel wants to kill these readers during the
@@ -153,6 +164,7 @@ class IPC_MOJO_EXPORT ChannelMojo
 
   void InitOnIOThread();
 
+#if !defined(USE_CHROME_EDK)
   static void CreateMessagingPipeOnIOThread(
       mojo::embedder::ScopedPlatformHandle handle,
       scoped_refptr<base::TaskRunner> callback_runner,
@@ -160,13 +172,16 @@ class IPC_MOJO_EXPORT ChannelMojo
   void OnMessagingPipeCreated(const CreateMessagingPipeCallback& callback,
                               mojo::ScopedMessagePipeHandle handle,
                               mojo::embedder::ChannelInfo* channel_info);
+#endif
 
   scoped_ptr<MojoBootstrap> bootstrap_;
   Listener* listener_;
   base::ProcessId peer_pid_;
   scoped_refptr<base::TaskRunner> io_runner_;
+#if !defined(USE_CHROME_EDK)
   scoped_ptr<mojo::embedder::ChannelInfo,
              ChannelInfoDeleter> channel_info_;
+#endif
 
   // Guards |message_reader_|, |waiting_connect_| and |pending_messages_|
   //