DevTools: [lighthouse] Implement performance metrics filmstrip

third_party/WebKit/Source/devtools/front_end/Runtime.js

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 546 matching lines @@
       var object = self;
       for (var i = 0; object && (i < path.length); ++i)
         object = object[path[i]];
       if (object)
         this._cachedTypeClasses[typeName] = /** @type function(new:Object) */ (object);
     }
     return this._cachedTypeClasses[typeName] || null;
   }
 
   /**
-   * @param {!Function} constructorFunction
-   * @return {!Object}
+   * @template T
+   * @param {function(new:T, ...)} constructorFunction
+   * @return {!T}
    */
   sharedInstance(constructorFunction) {
-    if (Runtime._instanceSymbol in constructorFunction)
-      return constructorFunction[Runtime._instanceSymbol];
-    var instance = new constructorFunction();
-    constructorFunction[Runtime._instanceSymbol] = instance;
-    return instance;
+    return singleton(constructorFunction);
   }
-}
-
-;
+};
 
 
 /**
  * @type {!Object.<string, string>}
  */
 Runtime._queryParamsObject = {
   __proto__: null
 };
 
 Runtime._instanceSymbol = Symbol('instance');
@@ skipping 535 matching lines @@
   send(message) {},
 
   /**
    * @return {!Promise<boolean>}
    */
   close() {}
 };
 
 /** @type {!Runtime} */
 var runtime;