[Chromoting] Add ability to enable/disable GDrive support per-app in gyp.

remoting/webapp/crd/js/client_session.js

Index: remoting/webapp/crd/js/client_session.js
diff --git a/remoting/webapp/crd/js/client_session.js b/remoting/webapp/crd/js/client_session.js
index 73bf54e140d656e608692780f81aaf345da29b51..33327b3aafe15708d343ca05e6677cb780347fb5 100644
--- a/remoting/webapp/crd/js/client_session.js
+++ b/remoting/webapp/crd/js/client_session.js
@@ -32,13 +32,6 @@ var remoting = remoting || {};
 remoting.ACCESS_TOKEN_RESEND_INTERVAL_MS = 15 * 60 * 1000;
 
 /**
- * True if Cast capability is supported.
- *
- * @type {boolean}
- */
-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.
@@ -1677,7 +1670,9 @@ remoting.ClientSession.prototype.processCastExtensionMessage_ = function(data) {
  * @private
  */
 remoting.ClientSession.prototype.createCastExtensionHandler_ = function() {
-  if (remoting.enableCast && this.mode_ == remoting.ClientSession.Mode.ME2ME) {
+  var capabilities = remoting.app.getRequiredCapabilities();
+  if (capabilities.indexOf(remoting.ClientSession.Capability.CAST) != -1 &&
+      this.mode_ == remoting.ClientSession.Mode.ME2ME) {
     this.castExtensionHandler_ = new remoting.CastExtensionHandler(this);
   }
 };