DevTools: migrate from external Maps to symbols in the bindings objects.

third_party/WebKit/Source/devtools/front_end/workspace/UISourceCode.js

 /*
  * Copyright (C) 2011 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 40 matching lines @@
         this._name += '?' + parsedURL.queryParams;
     } else {
       this._origin = '';
       this._parentURL = '';
       this._name = url;
     }
 
     this._contentType = contentType;
     /** @type {?Promise<?string>} */
     this._requestContentPromise = null;
-    /** @type {!Multimap<string, !Workspace.UISourceCode.LineMarker>} */
-    this._decorations = new Multimap();
-
-    /** @type {!Array.<!Workspace.Revision>} */
-    this.history = [];
-
-    /** @type {!Array<!Workspace.UISourceCode.Message>} */
-    this._messages = [];
-
+    /** @type {?Multimap<string, !Workspace.UISourceCode.LineMarker>} */
+    this._decorations = null;

[dgozman, 2017/01/04 01:04:08]

Do "Multimap|undefined" and don't assign here.

[pfeldman, 2017/01/04 01:13:48]

should be = null;

+    /** @type {?Array.<!Workspace.Revision>} */
+    this._history = [];

[dgozman, 2017/01/04 01:04:08]

ditto

[pfeldman, 2017/01/04 01:13:48]

Acknowledged.

+    /** @type {?Array<!Workspace.UISourceCode.Message>} */
+    this._messages = null;

[dgozman, 2017/01/04 01:04:08]

ditto

[pfeldman, 2017/01/04 01:13:48]

Acknowledged.

     this._contentLoaded = false;
     /** @type {?string} */
     this._content = null;
     this._forceLoadOnCheckContent = false;
     this._checkingContent = false;
     /** @type {?string} */
     this._lastAcceptedContent = null;
     /** @type {?string} */
     this._workingCopy = null;
     /** @type {?function() : string} */
@@ skipping 226 matching lines @@
   /**
    * @param {string} content
    * @param {boolean} committedByUser
    */
   _contentCommitted(content, committedByUser) {
     this._lastAcceptedContent = null;
     this._content = content;
     this._contentLoaded = true;
     this._requestContentPromise = null;
 
-    var lastRevision = this.history.length ? this.history[this.history.length - 1] : null;
+
+    if (!this._history)
+      this._history = [];
+
+    var lastRevision = this._history.length ? this._history[this._history.length - 1] : null;
     if (!lastRevision || lastRevision._content !== this._content) {
       var revision = new Workspace.Revision(this, this._content, new Date());
-      this.history.push(revision);
+      this._history.push(revision);
     }
 
     this._innerResetWorkingCopy();
     this.dispatchEventToListeners(
         Workspace.UISourceCode.Events.WorkingCopyCommitted, {uiSourceCode: this, content: content});
     this._project.workspace().dispatchEventToListeners(
         Workspace.Workspace.Events.WorkingCopyCommitted, {uiSourceCode: this, content: content});
     if (committedByUser) {
       this._project.workspace().dispatchEventToListeners(
           Workspace.Workspace.Events.WorkingCopyCommittedByUser, {uiSourceCode: this, content: content});
@@ skipping 46 matching lines @@
   revertAndClearHistory(callback) {
     /**
      * @this {Workspace.UISourceCode}
      * @param {?string} content
      */
     function revert(content) {
       if (typeof content !== 'string')
         return;
 
       this.addRevision(content);
-      this.history = [];
+      this._history = null;
       callback(this);
     }
 
     Host.userMetrics.actionTaken(Host.UserMetrics.Action.RevisionApplied);
     this.requestOriginalContent().then(revert.bind(this));
   }
 
   /**
+   * @return {!Array<!Workspace.Revision>}
+   */
+  history() {
+    if (!this._history)
+      this._history = [];
+    return this._history;
+  }
+
+  /**
    * @return {string}
    */
   workingCopy() {
     if (this._workingCopyGetter) {
       this._workingCopy = this._workingCopyGetter();
       this._workingCopyGetter = null;
     }
     if (this.isDirty())
       return /** @type {string} */ (this._workingCopy);
     return this._content || '';
@@ skipping 106 matching lines @@
   uiLocation(lineNumber, columnNumber) {
     if (typeof columnNumber === 'undefined')
       columnNumber = 0;
     return new Workspace.UILocation(this, lineNumber, columnNumber);
   }
 
   /**
    * @return {!Array<!Workspace.UISourceCode.Message>}
    */
   messages() {
-    return this._messages.slice();
+    return this._messages ? this._messages.slice() : [];
   }
 
   /**
    * @param {!Workspace.UISourceCode.Message.Level} level
    * @param {string} text
    * @param {number} lineNumber
    * @param {number=} columnNumber
    * @return {!Workspace.UISourceCode.Message} message
    */
   addLineMessage(level, text, lineNumber, columnNumber) {
     return this.addMessage(
         level, text, new Common.TextRange(lineNumber, columnNumber || 0, lineNumber, columnNumber || 0));
   }
 
   /**
    * @param {!Workspace.UISourceCode.Message.Level} level
    * @param {string} text
    * @param {!Common.TextRange} range
    * @return {!Workspace.UISourceCode.Message} message
    */
   addMessage(level, text, range) {
     var message = new Workspace.UISourceCode.Message(this, level, text, range);
+    if (!this._messages)
+      this._messages = [];
     this._messages.push(message);
     this.dispatchEventToListeners(Workspace.UISourceCode.Events.MessageAdded, message);
     return message;
   }
 
   /**
    * @param {!Workspace.UISourceCode.Message} message
    */
   removeMessage(message) {
-    if (this._messages.remove(message))
+    if (this._messages && this._messages.remove(message))
       this.dispatchEventToListeners(Workspace.UISourceCode.Events.MessageRemoved, message);
   }
 
   _removeAllMessages() {
-    var messages = this._messages;
-    this._messages = [];
-    for (var message of messages)
+    if (!this._messages)
+      return;
+    for (var message of this._messages)
       this.dispatchEventToListeners(Workspace.UISourceCode.Events.MessageRemoved, message);
+    this._messages = null;
   }
 
   /**
    * @param {number} lineNumber
    * @param {string} type
    * @param {?} data
    */
   addLineDecoration(lineNumber, type, data) {
     this.addDecoration(Common.TextRange.createFromLocation(lineNumber, 0), type, data);
   }
 
   /**
    * @param {!Common.TextRange} range
    * @param {string} type
    * @param {?} data
    */
   addDecoration(range, type, data) {
     var marker = new Workspace.UISourceCode.LineMarker(range, type, data);
+    if (!this._decorations)
+      this._decorations = new Multimap();
     this._decorations.set(type, marker);
     this.dispatchEventToListeners(Workspace.UISourceCode.Events.LineDecorationAdded, marker);
   }
 
   /**
    * @param {string} type
    */
   removeDecorationsForType(type) {
+    if (!this._decorations)
+      return;
     var markers = this._decorations.get(type);
     this._decorations.removeAll(type);
     markers.forEach(marker => {
       this.dispatchEventToListeners(Workspace.UISourceCode.Events.LineDecorationRemoved, marker);
     });
   }
 
   /**
    * @return {!Array<!Workspace.UISourceCode.LineMarker>}
    */
   allDecorations() {
-    return this._decorations.valuesArray();
+    return this._decorations ? this._decorations.valuesArray() : [];
   }
 
   removeAllDecorations() {
+    if (!this._decorations)
+      return;
     var decorationList = this._decorations.valuesArray();
     this._decorations.clear();
     decorationList.forEach(
         marker => this.dispatchEventToListeners(Workspace.UISourceCode.Events.LineDecorationRemoved, marker));
   }
 
   /**
    * @param {string} type
-   * @return {!Set<!Workspace.UISourceCode.LineMarker>}
+   * @return {?Set<!Workspace.UISourceCode.LineMarker>}
    */
   decorationsForType(type) {
-    return this._decorations.get(type);
+    return this._decorations ? this._decorations.get(type) : null;
   }
 };
 
 /** @enum {symbol} */
 Workspace.UISourceCode.Events = {
   WorkingCopyChanged: Symbol('WorkingCopyChanged'),
   WorkingCopyCommitted: Symbol('WorkingCopyCommitted'),
   TitleChanged: Symbol('TitleChanged'),
   MessageAdded: Symbol('MessageAdded'),
   MessageRemoved: Symbol('MessageRemoved'),
@@ skipping 276 matching lines @@
 Workspace.UISourceCodeMetadata = class {
   /**
    * @param {?Date} modificationTime
    * @param {?number} contentSize
    */
   constructor(modificationTime, contentSize) {
     this.modificationTime = modificationTime;
     this.contentSize = contentSize;
   }
 };