Revert of Making the Mojo Channel Messages legacy mode dynamic.

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
index c89039cea856945d5702c311a1e013cdb15ec7ea..97258e52f61d535bcf96f95be25ecf659fbefb56 100644
--- a/mojo/edk/embedder/embedder.h
+++ b/mojo/edk/embedder/embedder.h
@@ -73,13 +73,6 @@
 // cannot be associated with a specific child process.
 MOJO_SYSTEM_IMPL_EXPORT void SetDefaultProcessErrorCallback(
     const ProcessErrorCallback& callback);
-
-// Used to select whether mojo:edk::Channel should use the legacy or normal
-// header.
-// TODO(jcivelli): http://crbug.com/695645 remove this when legacy mode is not
-//                 in use anymore.
-MOJO_SYSTEM_IMPL_EXPORT void SetUseLegacyTransportProtocol(
-    bool use_legacy_protocol);
 
 // Basic functions -------------------------------------------------------------