[Chromoting] Enable support for mouselock in the webapp.

NOTRY=True
BUG=

Review URL: https://codereview.chromium.org/713423002

Cr-Commit-Position: refs/heads/master@{#303762}

remoting/webapp/crd/js/client_plugin.js

@@ -150,6 +150,11 @@ remoting.ClientPlugin.prototype.requestPairing =
  */
 remoting.ClientPlugin.prototype.onPinFetched = function(pin) {};
 
+/**
+ * Allows automatic mouse-lock.
+ */
+remoting.ClientPlugin.prototype.allowMouseLock = function() {};
+
 /**
  * Sets the third party authentication token and shared secret.
  *
@@ -289,6 +294,7 @@ remoting.ClientPlugin.Feature = {
   THIRD_PARTY_AUTH: 'thirdPartyAuth',
   TRAP_KEY: 'trapKey',
   PINLESS_AUTH: 'pinlessAuth',
+  ALLOW_MOUSE_LOCK: 'allowMouseLock',
   EXTENSION_MESSAGE: 'extensionMessage',
   MEDIA_SOURCE_RENDERING: 'mediaSourceRendering',
   VIDEO_CONTROL: 'videoControl'

remoting/webapp/crd/js/client_plugin_impl.js

@@ -850,6 +850,14 @@ remoting.ClientPluginImpl.prototype.useAsyncPinDialog =
       { method: 'useAsyncPinDialog', data: {} }));
 };
 
+/**
+ * Allows automatic mouse-lock.
+ */
+remoting.ClientPluginImpl.prototype.allowMouseLock = function() {
+  this.plugin_.postMessage(JSON.stringify(
+      { method: 'allowMouseLock', data: {} }));
+};
+
 /**
  * Sets the third party authentication token and shared secret.
  *

remoting/webapp/crd/js/client_session.js

@@ -29,6 +29,18 @@ var remoting = remoting || {};
  */
 remoting.enableCast = false;
 
+/**
+ * True to enable mouse lock.
+ * This is currently disabled because the current client plugin does not
+ * properly handle mouse lock and delegated large cursors at the same time.
+ * This should be re-enabled (by removing this flag) once a version of
+ * the plugin that supports both has reached Chrome Stable channel.
+ * (crbug.com/429322).
+ *
+ * @type {boolean}
+ */
+remoting.enableMouseLock = false;
+
 /**
  * @param {remoting.SignalStrategy} signalStrategy Signal strategy.
  * @param {HTMLElement} container Container element for the client view.
@@ -507,6 +519,13 @@ remoting.ClientSession.prototype.onPluginInitialized_ = function(initialized) {
     this.applyRemapKeys_(true);
   }
 
+  // TODO(wez): Only allow mouse lock if the app has the pointerLock permission.
+  // Enable automatic mouse-lock.
+  if (remoting.enableMouseLock &&
+      this.plugin_.hasFeature(remoting.ClientPlugin.Feature.ALLOW_MOUSE_LOCK)) {
+    this.plugin_.allowMouseLock();
+  }
+
   // Enable MediaSource-based rendering on Chrome 37 and above.
   var chromeVersionMajor =
       parseInt((remoting.getChromeVersion() || '0').split('.')[0], 10);