Make the embedder API use the ChannelManager.

mojo/edk/embedder/embedder_internal.h

Index: mojo/edk/embedder/embedder_internal.h
diff --git a/mojo/edk/embedder/embedder_internal.h b/mojo/edk/embedder/embedder_internal.h
index b8919b0008522eaeb7bdb2e186d5f5ae75a838b0..ab8388ae80596a22d063f78b71df68b086e9b499 100644
--- a/mojo/edk/embedder/embedder_internal.h
+++ b/mojo/edk/embedder/embedder_internal.h
@@ -2,22 +2,50 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// This header contains internal details for the *implementation* of the
+// embedder API. It should not be included by any public header (nor by users of
+// the embedder API).
+
 #ifndef MOJO_EDK_EMBEDDER_EMBEDDER_INTERNAL_H_
 #define MOJO_EDK_EMBEDDER_EMBEDDER_INTERNAL_H_
 
+#include <stdint.h>
+
 namespace mojo {
 
 namespace system {
+
+class ChannelManager;
 class Core;
+
+// Repeat a typedef in mojo/edk/system/channel_manager.h, to avoid including it.
+typedef uintptr_t ChannelId;
+
 }  // namespace system
 
 namespace embedder {
+
+// This is a type that's opaque to users of the embedder API (which only
+// gives/takes |ChannelInfo*|s). We make it a struct to make it
+// template-friendly.
+struct ChannelInfo {
+  explicit ChannelInfo(system::ChannelId channel_id = 0)
+      : channel_id(channel_id) {}
+
+  system::ChannelId channel_id;
+};
+
 namespace internal {
 
 // Instance of |Core| used by the system functions (|Mojo...()|).
 extern system::Core* g_core;
 
+// Instance of |ChannelManager| used by the channel management functions
+// (|mojo::embedder::CreateChannel()|, etc.).
+extern system::ChannelManager* g_channel_manager;
+
 }  // namespace internal
+
 }  // namepace embedder
 
 }  // namespace mojo