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

mojo/edk/embedder/embedder.h

Index: mojo/edk/embedder/embedder.h
diff --git a/mojo/edk/embedder/embedder.h b/mojo/edk/embedder/embedder.h
new file mode 100644
index 0000000000000000000000000000000000000000..30a548e5774277f5d28024ffc7f84604d1d5090c
--- /dev/null
+++ b/mojo/edk/embedder/embedder.h
@@ -0,0 +1,111 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MOJO_EDK_EMBEDDER_EMBEDDER_H_
+#define MOJO_EDK_EMBEDDER_EMBEDDER_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/task_runner.h"
+#include "mojo/edk/embedder/scoped_platform_handle.h"
+#include "mojo/edk/system/system_impl_export.h"
+#include "mojo/public/cpp/system/message_pipe.h"
+
+namespace mojo {
+namespace edk {
+
+class ProcessDelegate;
+
+// Basic configuration/initialization ------------------------------------------
+
+// |Init()| sets up the basic Mojo system environment, making the |Mojo...()|
+// functions available and functional. This is never shut down (except in tests
+// -- see test_embedder.h).
+
+// Allows changing the default max message size. Must be called before Init.
+MOJO_SYSTEM_IMPL_EXPORT void SetMaxMessageSize(size_t bytes);
+
+// Must be called first, or just after setting configuration parameters, to
+// initialize the (global, singleton) system.
+MOJO_SYSTEM_IMPL_EXPORT void Init();
+
+// Basic functions -------------------------------------------------------------
+
+// The functions in this section are available once |Init()| has been called.
+
+// Start waiting on the handle asynchronously. On success, |callback| will be
+// called exactly once, when |handle| satisfies a signal in |signals| or it
+// becomes known that it will never do so. |callback| will be executed on an
+// arbitrary thread, so it must not call any Mojo system or embedder functions.
+MOJO_SYSTEM_IMPL_EXPORT MojoResult
+AsyncWait(MojoHandle handle,
+          MojoHandleSignals signals,
+          const base::Callback<void(MojoResult)>& callback);
+
+// Creates a |MojoHandle| that wraps the given |PlatformHandle| (taking
+// ownership of it). This |MojoHandle| can then, e.g., be passed through message
+// pipes. Note: This takes ownership (and thus closes) |platform_handle| even on
+// failure, which is different from what you'd expect from a Mojo API, but it
+// makes for a more convenient embedder API.
+MOJO_SYSTEM_IMPL_EXPORT MojoResult
+CreatePlatformHandleWrapper(ScopedPlatformHandle platform_handle,
+                            MojoHandle* platform_handle_wrapper_handle);
+
+// Retrieves the |PlatformHandle| that was wrapped into a |MojoHandle| (using
+// |CreatePlatformHandleWrapper()| above). Note that the |MojoHandle| must still
+// be closed separately.
+MOJO_SYSTEM_IMPL_EXPORT MojoResult
+PassWrappedPlatformHandle(MojoHandle platform_handle_wrapper_handle,
+                          ScopedPlatformHandle* platform_handle);
+
+// Initialialization/shutdown for interprocess communication (IPC) -------------
+
+// |InitIPCSupport()| sets up the subsystem for interprocess communication,
+// making the IPC functions (in the following section) available and functional.
+// (This may only be done after |Init()|.)
+//
+// This subsystem may be shut down, using |ShutdownIPCSupportOnIOThread()| or
+// |ShutdownIPCSupport()|. None of the IPC functions may be called while or
+// after either of these is called.
+
+// Initializes a process of the given type; to be called after |Init()|.
+//   - |process_delegate| must be a process delegate of the appropriate type
+//     corresponding to |process_type|; its methods will be called on
+//     |delegate_thread_task_runner|.
+//   - |delegate_thread_task_runner|, |process_delegate|, and
+//     |io_thread_task_runner| should live at least until
+//     |ShutdownIPCSupport()|'s callback has been run or
+//     |ShutdownIPCSupportOnIOThread()| has completed.
+MOJO_SYSTEM_IMPL_EXPORT void InitIPCSupport(
+    scoped_refptr<base::TaskRunner> delegate_thread_task_runner,
+    ProcessDelegate* process_delegate,
+    scoped_refptr<base::TaskRunner> io_thread_task_runner);
+
+// Shuts down the subsystem initialized by |InitIPCSupport()|. This must be
+// called on the I/O thread (given to |InitIPCSupport()|). This completes
+// synchronously and does not result in a call to the process delegate's
+// |OnShutdownComplete()|.
+MOJO_SYSTEM_IMPL_EXPORT void ShutdownIPCSupportOnIOThread();
+
+// Like |ShutdownIPCSupportOnIOThread()|, but may be called from any thread,
+// signalling shutdown completion via the process delegate's
+// |OnShutdownComplete()|.
+MOJO_SYSTEM_IMPL_EXPORT void ShutdownIPCSupport();
+
+// Like above, but doesn't call |OnShutdownComplete| until all channels are
+// gone.
+// TODO(jam): this should be the default behavior.
+MOJO_SYSTEM_IMPL_EXPORT void ShutdownIPCSupportAndWaitForNoChannels();
+
+// Creates a message pipe from a platform handle. Safe to call from any thread.
+MOJO_SYSTEM_IMPL_EXPORT ScopedMessagePipeHandle
+CreateMessagePipe(ScopedPlatformHandle platform_handle);
+
+}  // namespace edk
+}  // namespace mojo
+
+#endif  // MOJO_EDK_EMBEDDER_EMBEDDER_H_