Eliminated named constants for instances of remoting.Error.

remoting/webapp/base/js/application.js

Index: remoting/webapp/base/js/application.js
diff --git a/remoting/webapp/base/js/application.js b/remoting/webapp/base/js/application.js
index f33f2eeb71cfbe09156d36438ae21108def7a658..40ee35fdb03490457e7cd8983ee1332972778b70 100644
--- a/remoting/webapp/base/js/application.js
+++ b/remoting/webapp/base/js/application.js
@@ -94,7 +94,7 @@ remoting.Application.prototype.start = function() {
       this.delegate_.start.bind(this.delegate_, this.getSessionConnector())
   ).catch(remoting.Error.handler(
       function(/** !remoting.Error */ error) {
-        if (error == remoting.Error.CANCELLED) {
+        if (error.hasTag(remoting.Error.Tag.CANCELLED)) {

[Jamie, 2015/03/12 21:40:11]

TBH, I have no problem with == (or === since it seems like the old code wasn't
consistent) here, but if you feel it's better encapsulated by hasTag, then the
tag member should probably be private.

[John Williams, 2015/03/13 00:26:35]

I wanted to discourage == or === in new code since it's easy to forget that
Error objects and error tags aren't comparable, and the compiler offers to help.

I had to add a getting and move some code from another file to make this work. 
What do you think of the result?

[Jamie, 2015/03/13 17:56:16]

What does the compiler do if you try to use == between a Error and a tag?
I think a straight getter would be cleaner. See my comments on that file.

[John Williams, 2015/03/13 19:30:29]

Nothing :-)  It compiles it just fine, but the comparison will always be false. 
Might be worth a feature request to the compiler team.

           that.exit();
         } else {
           that.delegate_.signInFailed(error);
@@ -115,7 +115,7 @@ remoting.Application.prototype.exit = function() {
 /** Disconnect the remoting client. */
 remoting.Application.prototype.disconnect = function() {
   if (remoting.clientSession) {
-    remoting.clientSession.disconnect(remoting.Error.NONE);
+    remoting.clientSession.disconnect(remoting.Error.none());
     console.log('Disconnected.');
   }
 };
@@ -236,7 +236,7 @@ remoting.Application.prototype.onClientStateChange_ = function(state) {
       var error = remoting.clientSession.getError();
       console.error('Client plugin reported connection failed: ' + error);
       if (error === null) {
-        error = remoting.Error.UNEXPECTED;
+        error = remoting.Error.unexpected();
       }
       this.onError(error);
       break;
@@ -245,7 +245,7 @@ remoting.Application.prototype.onClientStateChange_ = function(state) {
       console.error('Unexpected client plugin state: ' + state.current);
       // This should only happen if the web-app and client plugin get out of
       // sync, so MISSING_PLUGIN is a suitable error.
-      this.onError(remoting.Error.MISSING_PLUGIN);
+      this.onError(new remoting.Error(remoting.Error.Tag.MISSING_PLUGIN));
       break;
   }