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

mojo/runner/child_process_host.h

Index: mojo/runner/child_process_host.h
diff --git a/mojo/runner/child_process_host.h b/mojo/runner/child_process_host.h
index 8ab3147992b82e3faab43bde95d7ebf0b0e68b5c..2dd912fc0737b060817da4a3413e7b8649079ea6 100644
--- a/mojo/runner/child_process_host.h
+++ b/mojo/runner/child_process_host.h
@@ -8,12 +8,18 @@
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/process/process.h"
-#include "mojo/edk/embedder/channel_info_forward.h"
-#include "mojo/edk/embedder/platform_channel_pair.h"
-#include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/runner/child_process.mojom.h"
 #include "mojo/runner/child_process_host.h"
 
+#if defined(USE_CHROME_EDK)
+#include "mojo/edk/embedder/platform_channel_pair.h"
+#include "mojo/edk/embedder/scoped_platform_handle.h"
+#else
+#include "third_party/mojo/src/mojo/edk/embedder/channel_info_forward.h"
+#include "third_party/mojo/src/mojo/edk/embedder/platform_channel_pair.h"
+#include "third_party/mojo/src/mojo/edk/embedder/scoped_platform_handle.h"
+#endif
+
 namespace mojo {
 namespace runner {
 
@@ -65,8 +71,10 @@ class ChildProcessHost {
 
   void AppCompleted(int32_t result);
 
+#if !defined(USE_CHROME_EDK)
   // Callback for |embedder::CreateChannel()|.
   void DidCreateChannel(embedder::ChannelInfo* channel_info);
+#endif
 
   Context* const context_;
   bool start_sandboxed_;
@@ -74,7 +82,9 @@ class ChildProcessHost {
   base::Process child_process_;
   embedder::PlatformChannelPair platform_channel_pair_;
   ChildControllerPtr controller_;
+#if !defined(USE_CHROME_EDK)
   embedder::ChannelInfo* channel_info_;
+#endif
   ChildController::StartAppCallback on_app_complete_;
 
   // Platform-specific "pipe" to the child process. Valid immediately after