Add aliases to bot-page and refactor duplicated code

appengine/swarming/elements/res/js/alias.js

Index: appengine/swarming/elements/res/js/alias.js
diff --git a/appengine/swarming/elements/res/js/alias.js b/appengine/swarming/elements/res/js/alias.js
index f07faaa79ee013779b63ccdaa14a338061064196..6d4081fe4f0fec2268f34ab3b7c8e0c4d6cd1a77 100644
--- a/appengine/swarming/elements/res/js/alias.js
+++ b/appengine/swarming/elements/res/js/alias.js
@@ -60,9 +60,22 @@ this.swarming.alias = this.swarming.alias || (function(){
     return ANDROID_ALIASES[dt] || UNKNOWN;
   };
 
-  // alias.apply is the consistent way to modify a string to show its alias.
-  alias.apply = function(orig, alias) {
-    return alias +" ("+orig+")";
+  // alias.apply tries to alias the string "orig" based on what "type" it is.
+  // If type is in DIMENSIONS_WITH_ALIASES, the appropriate alias (e.g. gpu)
+  // is automatically applied.  Otherwise, "type" is treated as the alias.
+  // If type is known, but there is no matching alias (e.g. for gpu: FOOBAR)
+  // the original will be returned.
+  alias.apply = function(orig, type) {
+    var aliaser = aliasMap[type];
+    if (!aliaser) {
+      // treat type as the actual alias
+      return type + " ("+orig+")";
+    }
+    var alias = aliaser(orig);
+    if (alias !== "unknown") {
+      return alias + " ("+orig+")";
+    }
+    return orig;
   };
 
   alias.gpu = function(gpu) {
@@ -79,5 +92,10 @@ this.swarming.alias = this.swarming.alias || (function(){
     return str;
   };
 
+  var aliasMap = {
+    "device_type": alias.android,
+    "gpu": alias.gpu,
+  }
+
   return alias;
 })();