[AppRemoting] Drop the connection after resuming from a sleep > 30s.

Summary of changes:
1. Implements a resume detector by detecting differences in the time elapsed
   between ticks in setInterval().
2. Drops the connection if the client with ERROR_CLIENT_SUSPENDED if the webapp
   resumes from a sleep longer than 30s.
3. A follow up CL will be done to update the error code on the directory service.

BUG=486888

Review URL: https://codereview.chromium.org/1148993003

Cr-Commit-Position: refs/heads/master@{#331493}

7 files changed, 145 insertions, 27 deletions

diff --git a/remoting/remoting_webapp_files.gypi b/remoting/remoting_webapp_files.gypi
index 565a260..1310232 100644
--- a/remoting/remoting_webapp_files.gypi
+++ b/remoting/remoting_webapp_files.gypi
@@ -179,6 +179,7 @@
       'webapp/base/js/protocol_extension.js',
       'webapp/base/js/error.js',
       'webapp/base/js/plugin_settings.js',
+      'webapp/base/js/suspend_detector.js',
       'webapp/base/js/typecheck.js',
       'webapp/base/js/xhr.js',
     ],
diff --git a/remoting/webapp/app_remoting/js/app_remoting_activity.js b/remoting/webapp/app_remoting/js/app_remoting_activity.js
index 2697bbbd..ff4fb98 100644
--- a/remoting/webapp/app_remoting/js/app_remoting_activity.js
+++ b/remoting/webapp/app_remoting/js/app_remoting_activity.js
@@ -31,9 +31,6 @@ remoting.AppHostResponse;
  * @implements {remoting.Activity}
  */
 remoting.AppRemotingActivity = function(appCapabilities) {
-  /** @private {remoting.AppConnectedView} */
-  this.connectedView_ = null;
-
   /** @private */
   this.sessionFactory_ = new remoting.ClientSessionFactory(
       document.querySelector('#client-container .client-plugin-container'),
@@ -41,11 +38,13 @@ remoting.AppRemotingActivity = function(appCapabilities) {
 
   /** @private {remoting.ClientSession} */
   this.session_ = null;
+
+  /** @private {base.Disposables} */
+  this.connectedDisposables_ = null;
 };
 
 remoting.AppRemotingActivity.prototype.dispose = function() {
-  base.dispose(this.connectedView_);
-  this.connectedView_ = null;
+  this.cleanup_();
   remoting.LoadingWindow.close();
 };
 
@@ -67,8 +66,8 @@ remoting.AppRemotingActivity.prototype.stop = function() {
 
 /** @private */
 remoting.AppRemotingActivity.prototype.cleanup_ = function() {
-  base.dispose(this.connectedView_);
-  this.connectedView_ = null;
+  base.dispose(this.connectedDisposables_);
+  this.connectedDisposables_ = null;
   base.dispose(this.session_);
   this.session_ = null;
 };
@@ -160,7 +159,7 @@ remoting.AppRemotingActivity.prototype.onAppHostResponse_ =
  * @param {remoting.ConnectionInfo} connectionInfo
  */
 remoting.AppRemotingActivity.prototype.onConnected = function(connectionInfo) {
-  this.connectedView_ = new remoting.AppConnectedView(
+  var connectedView = new remoting.AppConnectedView(
       document.getElementById('client-container'), connectionInfo);
 
   var idleDetector = new remoting.IdleDetector(
@@ -171,6 +170,11 @@ remoting.AppRemotingActivity.prototype.onConnected = function(connectionInfo) {
   if (remoting.platformIsMac()) {
     connectionInfo.plugin().setRemapKeys('0x0700e3>0x0700e0,0x0700e7>0x0700e4');
   }
+
+  // Drop the session after 30s of suspension as we cannot recover from a
+  // connectivity loss longer than 30s anyways.
+  this.session_.dropSessionOnSuspend(30 * 1000);
+  this.connectedDisposables_ = new base.Disposables(connectedView);
 };
 
 /**
@@ -195,6 +199,11 @@ remoting.AppRemotingActivity.prototype.onConnectionFailed = function(error) {
 
 /** @private */
 remoting.AppRemotingActivity.prototype.onConnectionDropped_ = function() {
+  // Don't dispose the session here to keep the plugin alive so that we can show
+  // the last frame of the remote application window.
+  base.dispose(this.connectedDisposables_);
+  this.connectedDisposables_ = null;
+
   var rootElement = /** @type {HTMLDialogElement} */ (
       document.getElementById('connection-dropped-dialog'));
 
diff --git a/remoting/webapp/base/js/client_session.js b/remoting/webapp/base/js/client_session.js
index ff4c737..4ed7264 100644
--- a/remoting/webapp/base/js/client_session.js
+++ b/remoting/webapp/base/js/client_session.js
@@ -329,6 +329,29 @@ remoting.ClientSession.prototype.getError = function() {
 };
 
 /**
+ * Drop the session when the computer is suspended for more than
+ * |suspendDurationInMS|.
+ *
+ * @param {number} suspendDurationInMS maximum duration of suspension allowed
+ *     before the session will be dropped.
+ */
+remoting.ClientSession.prototype.dropSessionOnSuspend = function(
+    suspendDurationInMS) {
+  if (this.state_ !== remoting.ClientSession.State.CONNECTED) {
+    console.error('The session is not connected.');
+    return;
+  }
+
+  var suspendDetector = new remoting.SuspendDetector(suspendDurationInMS);
+  this.connectedDisposables_.add(
+      suspendDetector,
+      new base.EventHook(
+          suspendDetector, remoting.SuspendDetector.Events.resume,
+          this.disconnect.bind(
+              this, new remoting.Error(remoting.Error.Tag.CLIENT_SUSPENDED))));
+};
+
+/**
  * Called when the client receives its first frame.
  *
  * @return {void} Nothing.
@@ -492,6 +515,11 @@ remoting.ClientSession.prototype.isFinished = function() {
  * @private
  */
 remoting.ClientSession.prototype.setState_ = function(newState) {
+  // If we are at a finished state, ignore further state changes.
+  if (this.isFinished()) {
+    return;
+  }
+
   var oldState = this.state_;
   this.state_ = this.translateState_(oldState, newState);
 
diff --git a/remoting/webapp/base/js/error.js b/remoting/webapp/base/js/error.js
index d1dbbe24..b33115f 100644
--- a/remoting/webapp/base/js/error.js
+++ b/remoting/webapp/base/js/error.js
@@ -99,26 +99,30 @@ remoting.Error.Tag = {
   // not normally cause the error text to be shown to the user, so the
   // i18n-content prefix is not needed in this case.
   CANCELLED: '__CANCELLED__',
-
-  INVALID_ACCESS_CODE: /*i18n-content*/'ERROR_INVALID_ACCESS_CODE',
-  MISSING_PLUGIN: /*i18n-content*/'ERROR_MISSING_PLUGIN',
-  AUTHENTICATION_FAILED: /*i18n-content*/'ERROR_AUTHENTICATION_FAILED',
-  HOST_IS_OFFLINE: /*i18n-content*/'ERROR_HOST_IS_OFFLINE',
-  INCOMPATIBLE_PROTOCOL: /*i18n-content*/'ERROR_INCOMPATIBLE_PROTOCOL',
-  BAD_PLUGIN_VERSION: /*i18n-content*/'ERROR_BAD_PLUGIN_VERSION',
-  NETWORK_FAILURE: /*i18n-content*/'ERROR_NETWORK_FAILURE',
-  HOST_OVERLOAD: /*i18n-content*/'ERROR_HOST_OVERLOAD',
-  UNEXPECTED: /*i18n-content*/'ERROR_UNEXPECTED',
-  SERVICE_UNAVAILABLE: /*i18n-content*/'ERROR_SERVICE_UNAVAILABLE',
-  NOT_AUTHENTICATED: /*i18n-content*/'ERROR_NOT_AUTHENTICATED',
-  NOT_FOUND: /*i18n-content*/'ERROR_NOT_FOUND',
-  INVALID_HOST_DOMAIN: /*i18n-content*/'ERROR_INVALID_HOST_DOMAIN',
-  P2P_FAILURE: /*i18n-content*/'ERROR_P2P_FAILURE',
-  REGISTRATION_FAILED: /*i18n-content*/'ERROR_HOST_REGISTRATION_FAILED',
-  NOT_AUTHORIZED: /*i18n-content*/'ERROR_NOT_AUTHORIZED',
-
+  // Used to signify that the local computer was suspended for long enough that
+  // the connection is expected to drop, allowing a reconnect attempt to be
+  // scheduled sooner. This is not shownThis is not shown to the user so
+  // i18n-content prefix is not needed in this case.
+  CLIENT_SUSPENDED: '__CLIENT_SUSPENDED__',
+
+  INVALID_ACCESS_CODE: /*i18n-content*/ 'ERROR_INVALID_ACCESS_CODE',
+  MISSING_PLUGIN: /*i18n-content*/ 'ERROR_MISSING_PLUGIN',
+  AUTHENTICATION_FAILED: /*i18n-content*/ 'ERROR_AUTHENTICATION_FAILED',
+  HOST_IS_OFFLINE: /*i18n-content*/ 'ERROR_HOST_IS_OFFLINE',
+  INCOMPATIBLE_PROTOCOL: /*i18n-content*/ 'ERROR_INCOMPATIBLE_PROTOCOL',
+  BAD_PLUGIN_VERSION: /*i18n-content*/ 'ERROR_BAD_PLUGIN_VERSION',
+  NETWORK_FAILURE: /*i18n-content*/ 'ERROR_NETWORK_FAILURE',
+  HOST_OVERLOAD: /*i18n-content*/ 'ERROR_HOST_OVERLOAD',
+  UNEXPECTED: /*i18n-content*/ 'ERROR_UNEXPECTED',
+  SERVICE_UNAVAILABLE: /*i18n-content*/ 'ERROR_SERVICE_UNAVAILABLE',
+  NOT_AUTHENTICATED: /*i18n-content*/ 'ERROR_NOT_AUTHENTICATED',
+  NOT_FOUND: /*i18n-content*/ 'ERROR_NOT_FOUND',
+  INVALID_HOST_DOMAIN: /*i18n-content*/ 'ERROR_INVALID_HOST_DOMAIN',
+  P2P_FAILURE: /*i18n-content*/ 'ERROR_P2P_FAILURE',
+  REGISTRATION_FAILED: /*i18n-content*/ 'ERROR_HOST_REGISTRATION_FAILED',
+  NOT_AUTHORIZED: /*i18n-content*/ 'ERROR_NOT_AUTHORIZED',
   // TODO(garykac): Move app-specific errors into separate location.
-  APP_NOT_AUTHORIZED: /*i18n-content*/'ERROR_APP_NOT_AUTHORIZED'
+  APP_NOT_AUTHORIZED: /*i18n-content*/ 'ERROR_APP_NOT_AUTHORIZED'
 };
 
 // A whole bunch of semi-redundant constants, mostly to reduce to size
diff --git a/remoting/webapp/base/js/server_log_entry.js b/remoting/webapp/base/js/server_log_entry.js
index ec771a8..50bb11a 100644
--- a/remoting/webapp/base/js/server_log_entry.js
+++ b/remoting/webapp/base/js/server_log_entry.js
@@ -112,6 +112,8 @@ remoting.ServerLogEntry.getValueForError_ = function(connectionError) {
       return 'host-overload';
     case remoting.Error.Tag.P2P_FAILURE:
       return 'p2p-failure';
+    case remoting.Error.Tag.CLIENT_SUSPENDED:
+      return 'client-suspended';
     case remoting.Error.Tag.UNEXPECTED:
       return 'unexpected';
     default:
diff --git a/remoting/webapp/base/js/suspend_detector.js b/remoting/webapp/base/js/suspend_detector.js
new file mode 100644
index 0000000..241da49
--- /dev/null
+++ b/remoting/webapp/base/js/suspend_detector.js
@@ -0,0 +1,73 @@
+// 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.
+
+/** @suppress {duplicate} */
+var remoting = remoting || {};
+
+(function () {
+
+'use strict';
+
+var INTERVAL_IN_MS = 500;
+
+var TIMER_INACCURACY_IN_MS = 10;
+
+/**
+ * @constructor
+ * @param {number=} opt_maxSuspendInMs  The maximum permitted suspend duration
+ *     to raise the resume event.
+ * @extends {base.EventSourceImpl}
+ * @implements {base.Disposable}
+ */
+remoting.SuspendDetector = function(opt_maxSuspendInMs) {
+  base.inherits(this, base.EventSourceImpl);
+  this.defineEvents(base.values(remoting.SuspendDetector.Events));
+
+  if (!Number.isInteger(opt_maxSuspendInMs)) {
+    opt_maxSuspendInMs = TIMER_INACCURACY_IN_MS;
+  }
+
+  /** @private */
+  this.maxSuspendInMs_ = Math.max(opt_maxSuspendInMs, TIMER_INACCURACY_IN_MS);
+
+  /**
+   * JavaScript timer is paused while the computer is suspended, we need to use
+   * a higher resolution timer instead of |this.maxSuspendInMs_| to ensure the
+   * resume event fires promptly after the system wakes up from sleep.
+   * @private
+   */
+  this.timer_ =
+      new base.RepeatingTimer(this.onTick_.bind(this), INTERVAL_IN_MS);
+
+  /** @private */
+  this.lastTick_ = new Date();
+};
+
+remoting.SuspendDetector.prototype.dispose = function() {
+  base.dispose(this.timer_);
+  this.timer = null;
+};
+
+/** @private */
+remoting.SuspendDetector.prototype.onTick_ = function() {
+  var now = new Date();
+  // If the computer has just resumed from sleep, the sleep duration will
+  // roughly equal the |delta| between the ticks.
+  var delta = now - this.lastTick_;
+  this.lastTick_ = now;
+  if (delta > this.maxSuspendInMs_) {
+    this.raiseEvent(remoting.SuspendDetector.Events.resume, delta);
+  }
+};
+
+})();
+
+/** @enum {string} */
+remoting.SuspendDetector.Events = {
+  // Fired when the computer resumes up from sleep with the approximate sleep
+  // duration in milliseconds.  The sleep duration is only an approximation with
+  // and an uncertainty of |INTERVAL_IN_MS|.
+  //  {number} sleepDuration
+  resume: 'resume'
+};
diff --git a/remoting/webapp/files.gni b/remoting/webapp/files.gni
index dde5fa6..48b61da 100644
--- a/remoting/webapp/files.gni
+++ b/remoting/webapp/files.gni
@@ -174,6 +174,7 @@ remoting_webapp_shared_js_core_files = [
   "base/js/protocol_extension.js",
   "base/js/error.js",
   "base/js/plugin_settings.js",
+  "base/js/suspend_detector.js",
   "base/js/typecheck.js",
   "base/js/xhr.js",
 ]