The chromoting client sends simple logging to the server.

remoting/webapp/me2mom/client_session.js

 // Copyright (c) 2011 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.
 
 /**
  * @fileoverview
  * Class handling creation and teardown of a remoting client session.
  *
  * This abstracts a <embed> element and controls the plugin which does the
  * actual remoting work.  There should be no UI code inside this class.  It
@@ skipping 21 matching lines @@
                                   onStateChange) {
   this.state = remoting.ClientSession.State.CREATED;
 
   this.hostJid = hostJid;
   this.hostPublicKey = hostPublicKey;
   this.accessCode = accessCode;
   this.email = email;
   this.clientJid = '';
   this.sessionId = '';
   /** @type {remoting.ViewerPlugin} */ this.plugin = null;
-
+  this.logToServer = new remoting.LogToServer();
   this.onStateChange = onStateChange;
 };
 
 /** @enum {number} */
 remoting.ClientSession.State = {
   UNKNOWN: 0,
   CREATED: 1,
   BAD_PLUGIN_VERSION: 2,
   UNKNOWN_PLUGIN_ERROR: 3,
   CONNECTING: 4,
@@ skipping 266 matching lines @@
  * @private
  * @param {remoting.ClientSession.State} state The new state for the session.
  * @return {void} Nothing.
  */
 remoting.ClientSession.prototype.setState_ = function(state) {
   var oldState = this.state;
   this.state = state;
   if (this.onStateChange) {
     this.onStateChange(oldState);
   }
+  this.logToServer.logClientSessionStateChange(this.state, this.error);
 };
 
 /**
  * This is a callback that gets called when the window is resized.
  *
  * @return {void} Nothing.
  */
 remoting.ClientSession.prototype.onWindowSizeChanged = function() {
   remoting.debug.log('window size changed: ' +
                      window.innerWidth + 'x' +
@@ skipping 68 matching lines @@
   return {
     'video_bandwidth': this.plugin.videoBandwidth,
     'video_frame_rate': this.plugin.videoFrameRate,
     'capture_latency': this.plugin.videoCaptureLatency,
     'encode_latency': this.plugin.videoEncodeLatency,
     'decode_latency': this.plugin.videoDecodeLatency,
     'render_latency': this.plugin.videoRenderLatency,
     'roundtrip_latency': this.plugin.roundTripLatency
   };
 };