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

mojo/edk/embedder/platform_channel_utils_posix.h

Index: mojo/edk/embedder/platform_channel_utils_posix.h
diff --git a/third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h b/mojo/edk/embedder/platform_channel_utils_posix.h
similarity index 98%
copy from third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h
copy to mojo/edk/embedder/platform_channel_utils_posix.h
index 3073632e5098b2abbf17d46bfbb22466d9cbd110..00e6a16c6334c988f2fc019f67e6008547f3babf 100644
--- a/third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h
+++ b/mojo/edk/embedder/platform_channel_utils_posix.h
@@ -17,7 +17,7 @@
 struct iovec;  // Declared in <sys/uio.h>.
 
 namespace mojo {
-namespace embedder {
+namespace edk {
 
 // The maximum number of handles that can be sent "at once" using
 // |PlatformChannelSendmsgWithHandles()|.
@@ -70,7 +70,7 @@ PlatformChannelRecvmsg(PlatformHandle h,
                        size_t num_bytes,
                        std::deque<PlatformHandle>* platform_handles);
 
-}  // namespace embedder
+}  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_