Reduce the log level of frequently occuring DVLOGs

mojo/edk/system/message_pipe_dispatcher.cc

 // Copyright 2015 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/edk/system/message_pipe_dispatcher.h"
 
 #include <limits>
 #include <memory>
 
 #include "base/logging.h"
@@ skipping 123 matching lines @@
 
 MojoResult MessagePipeDispatcher::WriteMessage(
     std::unique_ptr<MessageForTransit> message,
     MojoWriteMessageFlags flags) {
   if (port_closed_ || in_transit_)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
   size_t num_bytes = message->num_bytes();
   int rv = node_controller_->SendMessage(port_, message->TakePortsMessage());
 
-  DVLOG(2) << "Sent message on pipe " << pipe_id_ << " endpoint " << endpoint_
+  DVLOG(4) << "Sent message on pipe " << pipe_id_ << " endpoint " << endpoint_
            << " [port=" << port_.name() << "; rv=" << rv
            << "; num_bytes=" << num_bytes << "]";
 
   if (rv != ports::OK) {
     if (rv == ports::ERROR_PORT_UNKNOWN ||
         rv == ports::ERROR_PORT_STATE_UNEXPECTED ||
         rv == ports::ERROR_PORT_CANNOT_SEND_PEER) {
       return MOJO_RESULT_INVALID_ARGUMENT;
     } else if (rv == ports::ERROR_PORT_PEER_CLOSED) {
       base::AutoLock lock(signal_lock_);
@@ skipping 374 matching lines @@
   ports::PortStatus port_status;
   if (node_controller_->node()->GetStatus(port_, &port_status) == ports::OK) {
     if (port_status.has_messages) {
       ports::ScopedMessage unused;
       size_t message_size = 0;
       node_controller_->node()->GetMessageIf(
           port_, [&message_size](const ports::Message& message) {
             message_size = message.num_payload_bytes();
             return false;
           }, &unused);
-      DVLOG(2) << "New message detected on message pipe " << pipe_id_
+      DVLOG(4) << "New message detected on message pipe " << pipe_id_
                << " endpoint " << endpoint_ << " [port=" << port_.name()
                << "; size=" << message_size << "]";
     }
     if (port_status.peer_closed) {
       DVLOG(2) << "Peer closure detected on message pipe " << pipe_id_
                << " endpoint " << endpoint_ << " [port=" << port_.name() << "]";
     }
   }
 #endif
 
   awakables_.AwakeForStateChange(GetHandleSignalsStateNoLock());
 }
 
 }  // namespace edk
 }  // namespace mojo