WIP: A couple of more ChannelMojo speedup ideas

ipc/mojo/ipc_message_pipe_reader.cc

Index: ipc/mojo/ipc_message_pipe_reader.cc
diff --git a/ipc/mojo/ipc_message_pipe_reader.cc b/ipc/mojo/ipc_message_pipe_reader.cc
index 72e7ad7618f4c31b2587bd554f0f6ff381a73a2d..b4d473ea408caaa57454404ba8a67430ee29d772 100644
--- a/ipc/mojo/ipc_message_pipe_reader.cc
+++ b/ipc/mojo/ipc_message_pipe_reader.cc
@@ -9,7 +9,6 @@
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop_proxy.h"
-#include "ipc/mojo/async_handle_waiter.h"
 #include "ipc/mojo/ipc_channel_mojo.h"
 
 namespace IPC {
@@ -19,9 +18,8 @@ MessagePipeReader::MessagePipeReader(mojo::ScopedMessagePipeHandle handle,
                                      MessagePipeReader::Delegate* delegate)
     : pipe_(handle.Pass()),
       delegate_(delegate),
-      async_waiter_(
-          new AsyncHandleWaiter(base::Bind(&MessagePipeReader::PipeIsReady,
-                                           base::Unretained(this)))) {
+      async_waiter_(new AsyncHandleWaiter(this)) {
+  async_waiter_->SetMessageCallback(pipe_.get().value());
 }
 
 MessagePipeReader::~MessagePipeReader() {
@@ -29,6 +27,8 @@ MessagePipeReader::~MessagePipeReader() {
 }
 
 void MessagePipeReader::Close() {
+  if (async_waiter_)
+    async_waiter_->ClearMessageCallback(pipe_.get().value());
   async_waiter_.reset();
   pipe_.reset();
   OnPipeClosed();
@@ -195,6 +195,13 @@ void MessagePipeReader::PipeIsReady(MojoResult wait_result) {
   ReadMessagesThenWait();
 }
 
+void MessagePipeReader::MessageWasArrived(const void* bytes,
+                                          uint32_t num_bytes) {
+  Message message(reinterpret_cast<const char*>(bytes),
+                  static_cast<int>(num_bytes));
+  delegate_->OnMessageReceived(message);
+}
+
 void MessagePipeReader::DelayedDeleter::operator()(
     MessagePipeReader* ptr) const {
   ptr->Close();