Support creating mojo peer connections from named pipes.

mojo/edk/embedder/platform_channel_utils_posix.h

Index: mojo/edk/embedder/platform_channel_utils_posix.h
diff --git a/mojo/edk/embedder/platform_channel_utils_posix.h b/mojo/edk/embedder/platform_channel_utils_posix.h
index 8b24bd028f8c872880efac80d2cfbe05ce533cbd..89a32e4fdf6fa2b49f3f2a19e9fb253fda9dc0e9 100644
--- a/mojo/edk/embedder/platform_channel_utils_posix.h
+++ b/mojo/edk/embedder/platform_channel_utils_posix.h
@@ -18,6 +18,7 @@ struct iovec;  // Declared in <sys/uio.h>.
 
 namespace mojo {
 namespace edk {
+class ScopedPlatformHandle;
 
 // The maximum number of handles that can be sent "at once" using
 // |PlatformChannelSendmsgWithHandles()|. This must be less than the Linux
@@ -70,6 +71,13 @@ PlatformChannelRecvmsg(PlatformHandle h,
                        std::deque<PlatformHandle>* platform_handles,
                        bool block = false);
 
+// Returns false if |server_handle| encounters an unrecoverable error.
+// Returns true if it's valid to keep listening on |server_handle|. In this
+// case, it's possible that a connection wasn't successfully established; then,
+// |connection_handle| will be invalid.
+bool ServerAcceptConnection(PlatformHandle server_handle,
+                            ScopedPlatformHandle* connection_handle);
+
 }  // namespace edk
 }  // namespace mojo