Remote assistance on Chrome OS Part VI - Enable It2me on ChromeOS in the webapp

remoting/webapp/crd/js/remoting.js

Index: remoting/webapp/crd/js/remoting.js
diff --git a/remoting/webapp/crd/js/remoting.js b/remoting/webapp/crd/js/remoting.js
index 50ff475e495cc337a4e1365a6a2951c07c050c12..4a843c9938ae335b7da0e5e57c295354ee492938 100644
--- a/remoting/webapp/crd/js/remoting.js
+++ b/remoting/webapp/crd/js/remoting.js
@@ -117,13 +117,17 @@ remoting.init = function() {
 
   remoting.initModalDialogs();
 
-  if (isHostModeSupported_()) {
-    var noShare = document.getElementById('chrome-os-no-share');
-    noShare.parentNode.removeChild(noShare);
-  } else {
-    var button = document.getElementById('share-button');
-    button.disabled = true;
-  }
+  isHostModeSupported_().then(
+    /** @param {Boolean} supported */
+    function(supported){
+      if (supported) {

[Jamie, 2014/11/03 19:41:34]

Part of the responsibility of the init method is to replace the "Loading..." UI
with the real UI once everything is ready. By making this asynchronous, is there
a risk of incomplete UI flashing briefly? You could move the call to setMode
into the promise resolution, but that might make the flow harder to understand.

[Jamie, 2014/11/03 23:15:11]

Given the difficulty in fixing this, the relative unlikliness of the problem
having a significant impact, and the fact that we should be able to remove this
code once all ChromeOS releases support sharing, I withdraw my objection. Please
add a TODO for that work.

+        var noShare = document.getElementById('chrome-os-no-share');
+        noShare.parentNode.removeChild(noShare);
+      } else {
+        var button = document.getElementById('share-button');
+        button.disabled = true;
+      }
+    });
 
   /**
    * @return {Promise} A promise that resolves to the id of the current
@@ -204,16 +208,6 @@ remoting.init = function() {
 };
 
 /**
- * Returns whether or not IT2Me is supported via the host NPAPI plugin.
- *
- * @return {boolean}
- */
-function isIT2MeSupported_() {
-  // Currently, IT2Me on Chromebooks is not supported.
-  return !remoting.runningOnChromeOS();
-}
-
-/**
  * Returns true if the current platform is fully supported. It's only used when
  * we detect that host native messaging components are not installed. In that
  * case the result of this function determines if the webapp should show the
@@ -249,7 +243,6 @@ remoting.onEmail = function(email) {
  */
 remoting.initHomeScreenUi = function() {
   remoting.hostController = new remoting.HostController();
-  document.getElementById('share-button').disabled = !isIT2MeSupported_();
   remoting.setMode(remoting.AppMode.HOME);
   remoting.hostSetupDialog =
       new remoting.HostSetupDialog(remoting.hostController);
@@ -401,13 +394,18 @@ function pluginGotCopy_(eventUncast) {
 }
 
 /**
- * Returns whether Host mode is supported on this platform.
+ * Returns whether Host mode is supported on this platform for It2me.
  *
- * @return {boolean} True if Host mode is supported.
+ * @return {Promise} Resolves to true if Host mode is supported.
  */
 function isHostModeSupported_() {
-  // Currently, sharing on Chromebooks is not supported.
-  return !remoting.runningOnChromeOS();
+  if (!remoting.platformIsChromeOS()) {
+    return Promise.resolve(true);
+  }
+  // Sharing on Chrome OS is currently behind a flag.
+  // isInstalled() will return false if the flag is disabled.
+  var hostInstaller = new remoting.HostInstaller();
+  return hostInstaller.isInstalled();
 }
 
 /**