Makes bindings work with nested message loops

mojo/public/cpp/bindings/lib/connector.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/public/cpp/bindings/lib/connector.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "base/logging.h"
@@ skipping 213 matching lines @@
   CHECK(!paused_);
 
   bool receiver_result = false;
 
   // Detect if |this| was destroyed during message dispatch. Allow for the
   // possibility of re-entering ReadMore() through message dispatch.
   bool was_destroyed_during_dispatch = false;
   bool* previous_destroyed_flag = destroyed_flag_;
   destroyed_flag_ = &was_destroyed_during_dispatch;
 
-  MojoResult rv = ReadAndDispatchMessage(
-      message_pipe_.get(), incoming_receiver_, &receiver_result);
-  if (read_result)
-    *read_result = rv;
+  Message message;
+  const MojoResult rv = ReadMessage(message_pipe_.get(), &message);
+  *read_result = rv;
+
+  if (rv == MOJO_RESULT_OK) {
+    // Dispatching the message may spin in a nested message loop. To ensure we
+    // continue dispatching messages when this happens start listening for
+    // messagse now.
+    if (!async_wait_id_)
+      WaitToReadMore();

[yzshen1, 2016/01/09 00:26:30]

Could you please add a TODO for evaluating the perf impact of this change?

[sky, 2016/01/11 16:10:35]

Done.

+    receiver_result =
+        incoming_receiver_ && incoming_receiver_->Accept(&message);
+  }
 
   if (was_destroyed_during_dispatch) {
     if (previous_destroyed_flag)
       *previous_destroyed_flag = true;  // Propagate flag.
     return false;
   }
+
   destroyed_flag_ = previous_destroyed_flag;
 
   if (rv == MOJO_RESULT_SHOULD_WAIT)
     return true;
 
   if (rv != MOJO_RESULT_OK) {
     HandleError(rv != MOJO_RESULT_FAILED_PRECONDITION, false);
     return false;
   }
 
@@ skipping 66 matching lines @@
     if (!paused_)
       WaitToReadMore();
   } else {
     error_ = true;
     connection_error_handler_.Run();
   }
 }
 
 }  // namespace internal
 }  // namespace mojo