DevTools: promisify ContentProvider.requestContent and all its clients.

third_party/WebKit/Source/devtools/front_end/sources/RevisionHistoryView.js

 /*
  * Copyright (C) 2012 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 191 matching lines @@
 {
     TreeElement.call(this, revision.timestamp.toLocaleTimeString(), true);
     this.selectable = false;
 
     this._revision = revision;
     this._baseRevision = baseRevision;
 
     this._revertElement = createElement("span");
     this._revertElement.className = "revision-history-link";
     this._revertElement.textContent = WebInspector.UIString("apply revision content");
-    this._revertElement.addEventListener("click", this._revision.revertToThis.bind(this._revision), false);
+    this._revertElement.addEventListener("click", event => {this._revision.revertToThis();}, false);
     if (!allowRevert)
         this._revertElement.classList.add("hidden");
 }
 
 WebInspector.RevisionHistoryTreeElement.prototype = {
     onattach: function()
     {
         this.listItemElement.classList.add("revision-history-revision");
     },
 
     onpopulate: function()
     {
         this.listItemElement.appendChild(this._revertElement);
 
         this.childrenListElement.classList.add("source-code");
-        if (this._baseRevision)
-            this._baseRevision.requestContent(step1.bind(this));
-        else
-            this._revision.uiSourceCode.requestOriginalContent(step1.bind(this));
-
-        /**
-         * @param {?string} baseContent
-         * @this {WebInspector.RevisionHistoryTreeElement}
-         */
-        function step1(baseContent)
-        {
-            this._revision.requestContent(step2.bind(this, baseContent));
-        }
+        Promise.all([
+            this._baseRevision ? this._baseRevision.requestContent() : this._revision.uiSourceCode.requestOriginalContent(),
+            this._revision.requestContent()
+        ]).spread(diff.bind(this));
 
         /**
          * @param {?string} baseContent
          * @param {?string} newContent
          * @this {WebInspector.RevisionHistoryTreeElement}
          */
-        function step2(baseContent, newContent)
+        function diff(baseContent, newContent)
         {
             var baseLines = baseContent.split("\n");
             var newLines = newContent.split("\n");
             var opcodes = WebInspector.Diff.lineDiff(baseLines, newLines);
             var lastWasSeparator = false;
 
             var baseLineNumber = 0;
             var newLineNumber = 0;
             for (var idx = 0; idx < opcodes.length; idx++) {
                 var code = opcodes[idx][0];
@@ skipping 55 matching lines @@
         contentSpan.classList.add("revision-history-line-" + changeType);
     },
 
     allowRevert: function()
     {
         this._revertElement.classList.remove("hidden");
     },
 
     __proto__: TreeElement.prototype
 }