DevTools: carefully cleanup CSS sourcemaps

third_party/WebKit/Source/devtools/front_end/bindings/SASSSourceMapping.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 31 matching lines @@
     this._networkProject = networkProject;
     this._workspace = workspace;
     this._eventListeners = [
       this._sourceMapManager.addEventListener(
           SDK.SourceMapManager.Events.SourceMapAttached, this._sourceMapAttached, this),
       this._sourceMapManager.addEventListener(
           SDK.SourceMapManager.Events.SourceMapDetached, this._sourceMapDetached, this),
       this._sourceMapManager.addEventListener(
           SDK.SourceMapManager.Events.SourceMapChanged, this._sourceMapChanged, this)
     ];
+
+    /** @type {!Multimap<string, !SDK.CSSStyleSheetHeader>} */
+    this._frameIdToHeaders = new Multimap();
   }
 
   /**
    * @param {?SDK.SourceMap} sourceMap
    */
   _sourceMapAttachedForTest(sourceMap) {
   }
 
   /**
    * @param {!Common.Event} event
    */
   _sourceMapAttached(event) {
     var header = /** @type {!SDK.CSSStyleSheetHeader} */ (event.data);
     var sourceMap = this._sourceMapManager.sourceMapForClient(header);
+    if (this._frameIdToHeaders.has(header.frameId)) {
+      this._frameIdToHeaders.set(header.frameId, header);
+      this._sourceMapAttachedForTest(sourceMap);
+      return;

[dgozman, 2017/03/28 23:37:37]

I haven't seen any difference in tests related to this early return. What
happens?

[lushnikov, 2017/03/29 01:27:24]

This stops over-writing sourcemap uiSourceCodes for every shadow dom. Tests
don't capture this kind of behavior

+    }
+    this._frameIdToHeaders.set(header.frameId, header);
+
     for (var sassURL of sourceMap.sourceURLs()) {
       var contentProvider = sourceMap.sourceContentProvider(sassURL, Common.resourceTypes.SourceMapStyleSheet);
       var embeddedContent = sourceMap.embeddedContentByURL(sassURL);
       var embeddedContentLength = typeof embeddedContent === 'string' ? embeddedContent.length : null;
       this._networkProject.addSourceMapFile(contentProvider, header.frameId, false, embeddedContentLength);
     }
     Bindings.cssWorkspaceBinding.updateLocations(header);
     this._sourceMapAttachedForTest(sourceMap);
   }
 
   /**
    * @param {!Common.Event} event
    */
   _sourceMapDetached(event) {
-    var header = /** @type {!SDK.CSSStyleSheetHeader} */ (event.data);
+    var header = /** @type {!SDK.CSSStyleSheetHeader} */ (event.data.client);
+    this._frameIdToHeaders.remove(header.frameId, header);
+    if (this._frameIdToHeaders.has(header.frameId))
+      return;
+    var sourceMap = /** @type {!SDK.SourceMap} */ (event.data.sourceMap);
+    for (var sassURL of sourceMap.sourceURLs())
+      this._networkProject.removeSourceMapFile(sassURL, header.frameId, false);
     Bindings.cssWorkspaceBinding.updateLocations(header);
   }
 
   /**
    * @param {!Common.Event} event
    */
   _sourceMapChanged(event) {
     var sourceMap = /** @type {!SDK.SourceMap} */ (event.data.sourceMap);
     var newSources = /** @type {!Map<string, string>} */ (event.data.newSources);
     var headers = this._sourceMapManager.clientsForSourceMap(sourceMap);
@@ skipping 32 matching lines @@
     var uiSourceCode = Bindings.NetworkProject.uiSourceCodeForStyleURL(this._workspace, entry.sourceURL, header);
     if (!uiSourceCode)
       return null;
     return uiSourceCode.uiLocation(entry.sourceLineNumber || 0, entry.sourceColumnNumber);
   }
 
   dispose() {
     Common.EventTarget.removeEventListeners(this._eventListeners);
   }
 };