DevTools: carefully cleanup CSS sourcemaps

third_party/WebKit/Source/devtools/front_end/bindings/SASSSourceMapping.js

Index: third_party/WebKit/Source/devtools/front_end/bindings/SASSSourceMapping.js
diff --git a/third_party/WebKit/Source/devtools/front_end/bindings/SASSSourceMapping.js b/third_party/WebKit/Source/devtools/front_end/bindings/SASSSourceMapping.js
index f7f9507e992356c1760e94384e3a0ba82bf0ed7f..325a15d238d92387086bc074cffea49bacfabbe9 100644
--- a/third_party/WebKit/Source/devtools/front_end/bindings/SASSSourceMapping.js
+++ b/third_party/WebKit/Source/devtools/front_end/bindings/SASSSourceMapping.js
@@ -49,6 +49,9 @@ Bindings.SASSSourceMapping = class {
       this._sourceMapManager.addEventListener(
           SDK.SourceMapManager.Events.SourceMapChanged, this._sourceMapChanged, this)
     ];
+
+    /** @type {!Multimap<string, !SDK.CSSStyleSheetHeader>} */
+    this._frameIdToHeaders = new Multimap();
   }
 
   /**
@@ -63,6 +66,13 @@ Bindings.SASSSourceMapping = class {
   _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);
@@ -77,7 +87,13 @@ Bindings.SASSSourceMapping = class {
    * @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);
   }