DevTools: introduce WI.ASTService instead of WI.SASSWorkspaceAdapter

The patch kill WI.SASSWorkspaceAdapter altogether and replaces it with
WI.ASTService.

BUG=527993
R=pfeldman, dgozman

Review URL: https://codereview.chromium.org/1692273004

Cr-Commit-Position: refs/heads/master@{#376404}

11 files changed, 168 insertions, 780 deletions

diff --git a/third_party/WebKit/LayoutTests/inspector/sass/sass-test.js b/third_party/WebKit/LayoutTests/inspector/sass/sass-test.js
index 96eb57f..3fd00a2 100644
--- a/third_party/WebKit/LayoutTests/inspector/sass/sass-test.js
+++ b/third_party/WebKit/LayoutTests/inspector/sass/sass-test.js
@@ -2,26 +2,18 @@ var initialize_SassTest = function() {
 
 InspectorTest.preloadModule("sass");
 
-var sassWorkspaceAdapter = null;
-InspectorTest.sassWorkspaceAdapter = function()
-{
-    if (!sassWorkspaceAdapter)
-        sassWorkspaceAdapter = new WebInspector.SASSWorkspaceAdapter(InspectorTest.cssModel, WebInspector.workspace, WebInspector.networkMapping);
-    return sassWorkspaceAdapter;
-}
+var cssParserService = null;
 
-var cssParser = null;
-
-InspectorTest.cssParser = function()
+InspectorTest.cssParserService = function()
 {
-    if (!cssParser)
-        cssParser = new WebInspector.CSSParser();
-    return cssParser;
+    if (!cssParserService)
+        cssParserService = new WebInspector.CSSParserService();
+    return cssParserService;
 }
 
 InspectorTest.parseCSS = function(url, text)
 {
-    return WebInspector.SASSSupport.parseCSS(InspectorTest.cssParser(), url, text);
+    return WebInspector.SASSSupport.parseCSS(InspectorTest.cssParserService(), url, text);
 }
 
 InspectorTest.parseSCSS = function(url, text)
@@ -31,37 +23,22 @@ InspectorTest.parseSCSS = function(url, text)
 
     function onTokenizer(tokenizer)
     {
-        return WebInspector.SASSSupport.parseSCSS(url, text, tokenizer);
+        return WebInspector.SASSSupport.parseSCSS(tokenizer, url, text);
     }
 }
 
 InspectorTest.loadASTMapping = function(header, callback)
 {
-    console.assert(header.cssModel() === InspectorTest.sassWorkspaceAdapter()._cssModel, "The header could not be processed by main target workspaceAdapter");
-    var tokenizerFactory = null;
-    var sourceMap = null;
 
     var completeSourceMapURL = WebInspector.ParsedURL.completeURL(header.sourceURL, header.sourceMapURL);
     WebInspector.SourceMap.load(completeSourceMapURL, header.sourceURL, onSourceMapLoaded);
 
-    self.runtime.instancePromise(WebInspector.TokenizerFactory)
-        .then(tf => tokenizerFactory = tf)
-        .then(maybeStartLoading);
-
-    function onSourceMapLoaded(sm)
-    {
-        sourceMap = sm;
-        maybeStartLoading();
-    }
-
-    function maybeStartLoading()
+    function onSourceMapLoaded(sourceMap)
     {
-        if (!sourceMap || !tokenizerFactory)
-            return;
-        var client = InspectorTest.sassWorkspaceAdapter().trackSources(sourceMap);
-        WebInspector.SASSLiveSourceMap._loadMapping(client, InspectorTest.cssParser(), tokenizerFactory, sourceMap)
-            .then(callback)
-            .then(() => client.dispose())
+        var astService = new WebInspector.ASTService();
+        WebInspector.SASSLiveSourceMap._createASTMapping(astService, header.cssModel(), sourceMap)
+            .then(mapping => callback(mapping))
+            .then(() => astService.dispose());
     }
 }
 
diff --git a/third_party/WebKit/LayoutTests/inspector/sass/test-workspace-adapter-expected.txt b/third_party/WebKit/LayoutTests/inspector/sass/test-workspace-adapter-expected.txt
deleted file mode 100644
index b230107..0000000
--- a/third_party/WebKit/LayoutTests/inspector/sass/test-workspace-adapter-expected.txt
+++ /dev/null
@@ -1,73 +0,0 @@
-Verify SourceMapTracker functionality.
-
-
-Running: loadFileSystemResources
-
-Running: loadCSSResources
-
-Running: mutateCSS
- -- TRACKER 1 -- SourceChanged event: all.css
- -- TRACKER 1 -- SourceChanged event: all.css
-== Outdated ==
-TRACKER 1: true
-TRACKER 2: false
- -- TRACKER 2 -- SourceChanged event: print.css
-== Outdated ==
-TRACKER 1: true
-TRACKER 2: true
-== Contents ==
-content of print.css: <all.css update 1>
-content of print.css: <print.css update 1>
-== Outdated ==
-TRACKER 1: false
-TRACKER 2: false
-
-Running: mutateSASS
- -- TRACKER 1 -- SourceChanged event: file:///var/www/a.scss
-== Outdated ==
-TRACKER 1: true
-TRACKER 2: false
- -- TRACKER 2 -- SourceChanged event: file:///var/www/b.scss
-== Outdated ==
-TRACKER 1: true
-TRACKER 2: true
-== Contents ==
-content of file:///var/www/b.scss: <a.scss update 1>
-content of file:///var/www/b.scss: <b.scss update 1>
-== Outdated ==
-TRACKER 1: false
-TRACKER 2: false
-
-Running: mutateSASSCommon
- -- TRACKER 1 -- SourceChanged event: file:///var/www/common.scss
- -- TRACKER 2 -- SourceChanged event: file:///var/www/common.scss
-== Outdated ==
-TRACKER 1: true
-TRACKER 2: true
-== Contents ==
-content of file:///var/www/common.scss: <common.scss update 1>
-content of file:///var/www/common.scss: <common.scss update 1>
-== Outdated ==
-TRACKER 1: false
-TRACKER 2: false
-
-Running: trackerSetCSS
-tracker1.setCSSText result: true
-tracker2.setCSSText result: true
-== Contents ==
-content of print.css: <all.css TRACKER 1>
-content of print.css: <print.css TRACKER 2>
-
-Running: trackerSetSASSCommon
-tracker1.setSASSText result: true
- -- TRACKER 2 -- SourceChanged event: file:///var/www/common.scss
-== Outdated ==
-TRACKER 1: false
-TRACKER 2: true
-
-Running: removeFirstTrackerStyleSheets
- -- TRACKER 1 -- TrackingStopped
-
-Running: removeSecondTrackerStyleSheets
- -- TRACKER 2 -- TrackingStopped
-
diff --git a/third_party/WebKit/LayoutTests/inspector/sass/test-workspace-adapter.html b/third_party/WebKit/LayoutTests/inspector/sass/test-workspace-adapter.html
deleted file mode 100644
index 9243eed..0000000
--- a/third_party/WebKit/LayoutTests/inspector/sass/test-workspace-adapter.html
+++ /dev/null
@@ -1,189 +0,0 @@
-<html>
-<head>
-
-<script src="../../http/tests/inspector/inspector-test.js"></script>
-<script src="../../http/tests/inspector/debugger-test.js"></script>
-<script src="../../http/tests/inspector/isolated-filesystem-test.js"></script>
-<script src="./sass-test.js"></script>
-<script>
-
-var styles = [];
-function addStyleSheets()
-{
-    for (var i = 0; i < 2; ++i) {
-        var style = document.createElement("style");
-        style.textContent = "<all.css content>\n/*# sourceURL=all.css */";
-        document.head.appendChild(style);
-        styles.push(style);
-    }
-
-    var style = document.createElement("style");
-    style.textContent = "<print.css content>\n/*# sourceURL=print.css */";
-    document.head.appendChild(style);
-    styles.push(style);
-}
-
-function removeStyles(amount)
-{
-    for (var i = 0; i < amount; ++i)
-        styles.shift().remove();
-}
-
-function test()
-{
-    function createTracker(trackerName, cssURL, sassURLs)
-    {
-        var sources = sassURLs;
-        var fakeSourceMap = {
-            sources: () => sources,
-            compiledURL: () => cssURL
-        };
-        var tracker = InspectorTest.sassWorkspaceAdapter().trackSources(fakeSourceMap);
-        tracker.__NAME = trackerName;
-        tracker.addEventListener(WebInspector.SourceMapTracker.Events.SourceChanged, onSourceChanged);
-        tracker.addEventListener(WebInspector.SourceMapTracker.Events.TrackingStopped, onTrackingStopped);
-        return tracker;
-
-        function onSourceChanged(event)
-        {
-            InspectorTest.addResult(" -- " + event.target.__NAME + " -- SourceChanged event: " + event.data);
-        }
-
-        function onTrackingStopped(event)
-        {
-            InspectorTest.addResult(" -- " + event.target.__NAME + " -- TrackingStopped");
-        }
-    }
-
-    var fileSystemPrefix = "file:///var/www";
-    var css1 = "all.css";
-    var css2 = "print.css";
-    var sass1 = fileSystemPrefix + "/a.scss";
-    var sass2 = fileSystemPrefix + "/b.scss";
-    var sassCommon = fileSystemPrefix + "/common.scss";
-    var tracker1 = createTracker("TRACKER 1", css1, [sass1, sassCommon]);
-    var tracker2 = createTracker("TRACKER 2", css2, [sass2, sassCommon]);
-
-    InspectorTest.runTestSuite([
-        function loadFileSystemResources(next)
-        {
-            var fs = new InspectorTest.TestFileSystem(fileSystemPrefix);
-            fs.addFileMapping(fileSystemPrefix, "/");
-            fs.root.addFile("common.scss", "<common.scss content>");
-            fs.root.addFile("a.scss", "<a.scss content>");
-            fs.root.addFile("b.scss", "<b.scss content>");
-            fs.reportCreated(next);
-        },
-
-        function loadCSSResources(next)
-        {
-            InspectorTest.evaluateInPage("addStyleSheets()", next);
-        },
-
-        function mutateCSS(next)
-        {
-            InspectorTest.updateCSSText(css1, "<all.css update 1>")
-                .then(checkOutdated)
-                .then(() => InspectorTest.updateCSSText(css2, "<print.css update 1>"))
-                .then(checkOutdated)
-                .then(() => requestContent([css1], [css2]))
-                .then(checkOutdated)
-                .then(next);
-        },
-
-        function mutateSASS(next)
-        {
-            InspectorTest.updateSASSText(sass1, "<a.scss update 1>");
-            checkOutdated();
-            InspectorTest.updateSASSText(sass2, "<b.scss update 1>");
-            checkOutdated();
-            requestContent([sass1], [sass2])
-                .then(checkOutdated)
-                .then(next);
-        },
-
-        function mutateSASSCommon(next)
-        {
-            InspectorTest.updateSASSText(sassCommon, "<common.scss update 1>");
-            checkOutdated();
-            requestContent([sassCommon], [sassCommon])
-                .then(checkOutdated)
-                .then(next);
-        },
-
-        function trackerSetCSS(next)
-        {
-            var result = tracker1.setCSSText("<all.css TRACKER 1>", []);
-            InspectorTest.addResult("tracker1.setCSSText result: " + result);
-            var result = tracker2.setCSSText("<print.css TRACKER 2>", []);
-            InspectorTest.addResult("tracker2.setCSSText result: " + result);
-            requestContent([css1], [css2])
-                .then(next);
-        },
-
-        function trackerSetSASSCommon(next)
-        {
-            var result = tracker1.setSASSText(sassCommon, "<common.scss TRACKER 1>");
-            InspectorTest.addResult("tracker1.setSASSText result: " + result);
-            awaitSourceChanges(tracker2, sassCommon)
-                .then(checkOutdated)
-                .then(next);
-        },
-
-        function removeFirstTrackerStyleSheets(next)
-        {
-            InspectorTest.evaluateInPage("removeStyles(2)", next);
-        },
-
-        function removeSecondTrackerStyleSheets(next)
-        {
-            InspectorTest.evaluateInPage("removeStyles(1)", next);
-        },
-    ]);
-
-    function awaitSourceChanges(tracker, url)
-    {
-        var callback;
-        var promise = new Promise(fulfill => callback = fulfill);
-        tracker.addEventListener(WebInspector.SourceMapTracker.Events.SourceChanged, onSourceChanged);
-        return promise;
-
-        function onSourceChanged(event)
-        {
-            if (event.data !== url)
-                return;
-            tracker.removeEventListener(WebInspector.SourceMapTracker.Events.SourceChanged, onSourceChanged);
-            callback();
-        }
-    }
-
-    function checkOutdated()
-    {
-        InspectorTest.addResult("== Outdated ==");
-        InspectorTest.addResult(tracker1.__NAME + ": " + tracker1.isOutdated());
-        InspectorTest.addResult(tracker2.__NAME + ": " + tracker2.isOutdated());
-    }
-
-    function requestContent(urls1, urls2)
-    {
-        InspectorTest.addResult("== Contents ==");
-        urls1 = urls1 || [];
-        urls2 = urls2 || [];
-        var onContent = (url, content) => InspectorTest.addResult("content of " + url + ": " + content);
-        var promises = [];
-        for (var url of urls1)
-            promises.push(tracker1.content(url).then(text => onContent(url, text)));
-        for (var url of urls2)
-            promises.push(tracker2.content(url).then(text => onContent(url, text)));
-        return Promise.all(promises);
-    }
-}
-
-</script>
-
-</head>
-
-<body onload="runTest()">
-<p>Verify SourceMapTracker functionality.</p>
-</body>
-</html>
diff --git a/third_party/WebKit/Source/devtools/devtools.gypi b/third_party/WebKit/Source/devtools/devtools.gypi
index 7b940d2..9f902ef 100644
--- a/third_party/WebKit/Source/devtools/devtools.gypi
+++ b/third_party/WebKit/Source/devtools/devtools.gypi
@@ -118,8 +118,8 @@
             'front_end/host/UserMetrics.js',
         ],
         'devtools_sass_js_files': [
+            'front_end/sass/ASTService.js',
             'front_end/sass/SASSLiveSourceMap.js',
-            'front_end/sass/SASSWorkspaceAdapter.js',
             'front_end/sass/SASSSupport.js',
         ],
         'devtools_screencast_js_files': [
diff --git a/third_party/WebKit/Source/devtools/front_end/sass/ASTService.js b/third_party/WebKit/Source/devtools/front_end/sass/ASTService.js
new file mode 100644
index 0000000..4d6e2ba
--- /dev/null
+++ b/third_party/WebKit/Source/devtools/front_end/sass/ASTService.js
@@ -0,0 +1,45 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @constructor
+ */
+WebInspector.ASTService = function()
+{
+    this._cssParserService = new WebInspector.CSSParserService();
+    this._sassInitPromise = self.runtime.instancePromise(WebInspector.TokenizerFactory);
+    this._terminated = false;
+}
+
+WebInspector.ASTService.prototype = {
+    /**
+     * @param {string} url
+     * @param {string} text
+     * @return {!Promise<!WebInspector.SASSSupport.AST>}
+     */
+    parseCSS: function(url, text)
+    {
+        console.assert(!this._terminated, "Illegal call parseCSS on terminated ASTService.");
+        return WebInspector.SASSSupport.parseCSS(this._cssParserService, url, text);
+    },
+
+    /**
+     * @param {string} url
+     * @param {string} text
+     * @return {!Promise<!WebInspector.SASSSupport.AST>}
+     */
+    parseSCSS: function(url, text)
+    {
+        console.assert(!this._terminated, "Illegal call parseSCSS on terminated ASTService.");
+        return this._sassInitPromise.then(tokenizer => WebInspector.SASSSupport.parseSCSS(tokenizer, url, text));
+    },
+
+    dispose: function()
+    {
+        if (this._terminated)
+            return;
+        this._terminated = true;
+        this._cssParserService.dispose();
+    },
+}
diff --git a/third_party/WebKit/Source/devtools/front_end/sass/SASSLiveSourceMap.js b/third_party/WebKit/Source/devtools/front_end/sass/SASSLiveSourceMap.js
index 6c49db3..ba772cf 100644
--- a/third_party/WebKit/Source/devtools/front_end/sass/SASSLiveSourceMap.js
+++ b/third_party/WebKit/Source/devtools/front_end/sass/SASSLiveSourceMap.js
@@ -5,29 +5,35 @@
 WebInspector.SASSLiveSourceMap = {}
 
 /**
- * @param {!WebInspector.SourceMapTracker} tracker
- * @param {!WebInspector.CSSParser} cssParser
- * @param {!WebInspector.TokenizerFactory} tokenizer
+ * @param {!WebInspector.ASTService} astService
+ * @param {!WebInspector.CSSStyleModel} cssModel
+ * @param {!WebInspector.SourceMap} sourceMap
  * @return {!Promise<?WebInspector.SASSLiveSourceMap.CSSToSASSMapping>}
  */
-WebInspector.SASSLiveSourceMap._loadMapping = function(tracker, cssParser, tokenizer)
+WebInspector.SASSLiveSourceMap._createASTMapping = function(astService, cssModel, sourceMap)
 {
+    var headerIds = cssModel.styleSheetIdsForURL(sourceMap.compiledURL());
+    if (!headerIds || !headerIds.length)
+        return Promise.resolve(/** @type {?WebInspector.SASSLiveSourceMap.CSSToSASSMapping} */(null));
+    var header = cssModel.styleSheetHeaderForId(headerIds[0]);
+
     var sassModels = new Map();
     var cssAST = null;
     var promises = [];
-    for (var url of tracker.sassURLs()) {
-        var sassPromise = tracker.content(url)
-            .then(text => WebInspector.SASSSupport.parseSCSS(url, text, tokenizer))
+    for (var url of sourceMap.sources()) {
+        var contentProvider = sourceMap.sourceContentProvider(url, WebInspector.resourceTypes.SourceMapStyleSheet);
+        var sassPromise = contentProvider.requestContent()
+            .then(text => astService.parseSCSS(url, text || ""))
             .then(ast => sassModels.set(url, ast));
         promises.push(sassPromise);
     }
-    var cssPromise = tracker.content(tracker.cssURL())
-        .then(text => WebInspector.SASSSupport.parseCSS(cssParser, tracker.cssURL(), text))
+    var cssPromise = header.requestContent()
+        .then(text => astService.parseCSS(sourceMap.compiledURL(), text || ""))
         .then(ast => cssAST = ast);
     promises.push(cssPromise);
 
     return Promise.all(promises)
-        .then(() => WebInspector.SASSLiveSourceMap.CSSToSASSMapping.fromSourceMap(tracker.sourceMap(), cssAST, sassModels))
+        .then(() => WebInspector.SASSLiveSourceMap.CSSToSASSMapping.fromSourceMap(sourceMap, cssAST, sassModels))
         .catchException(/** @type {?WebInspector.SASSLiveSourceMap.CSSToSASSMapping} */(null));
 }
 
diff --git a/third_party/WebKit/Source/devtools/front_end/sass/SASSSupport.js b/third_party/WebKit/Source/devtools/front_end/sass/SASSSupport.js
index 0ed1943..7120d7f 100644
--- a/third_party/WebKit/Source/devtools/front_end/sass/SASSSupport.js
+++ b/third_party/WebKit/Source/devtools/front_end/sass/SASSSupport.js
@@ -5,14 +5,14 @@
 WebInspector.SASSSupport = {}
 
 /**
- * @param {!WebInspector.CSSParser} parser
+ * @param {!WebInspector.CSSParserService} cssParserService
  * @param {string} url
  * @param {string} text
  * @return {!Promise<!WebInspector.SASSSupport.AST>}
  */
-WebInspector.SASSSupport.parseCSS = function(parser, url, text)
+WebInspector.SASSSupport.parseCSS = function(cssParserService, url, text)
 {
-    return parser.parsePromise(text)
+    return cssParserService.parseCSS(text)
         .then(onParsed);
 
     /**
@@ -42,12 +42,12 @@ WebInspector.SASSSupport.parseCSS = function(parser, url, text)
 }
 
 /**
+ * @param {!WebInspector.TokenizerFactory} tokenizerFactory
  * @param {string} url
  * @param {string} text
- * @param {!WebInspector.TokenizerFactory} tokenizerFactory
  * @return {!WebInspector.SASSSupport.AST}
  */
-WebInspector.SASSSupport.parseSCSS = function(url, text, tokenizerFactory)
+WebInspector.SASSSupport.parseSCSS = function(tokenizerFactory, url, text)
 {
     var document = new WebInspector.SASSSupport.ASTDocument(url, text);
     var result = WebInspector.SASSSupport._innerParseSCSS(document, tokenizerFactory);
diff --git a/third_party/WebKit/Source/devtools/front_end/sass/SASSWorkspaceAdapter.js b/third_party/WebKit/Source/devtools/front_end/sass/SASSWorkspaceAdapter.js
deleted file mode 100644
index 5dc3292..0000000
--- a/third_party/WebKit/Source/devtools/front_end/sass/SASSWorkspaceAdapter.js
+++ /dev/null
@@ -1,461 +0,0 @@
-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-/**
- * @constructor
- * @param {!WebInspector.CSSStyleModel} cssModel
- * @param {!WebInspector.Workspace} workspace
- * @param {!WebInspector.NetworkMapping} networkMapping
- */
-WebInspector.SASSWorkspaceAdapter = function(cssModel, workspace, networkMapping)
-{
-    this._workspace = workspace;
-    this._networkMapping = networkMapping;
-    this._cssModel = cssModel;
-
-    /** @type {!Map<string, number>} */
-    this._versions = new Map();
-    /** @type {!Map<string, !Promise<boolean>>} */
-    this._awaitingPromises = new Map();
-    /** @type {!Map<string, function(boolean)>} */
-    this._awaitingFulfills = new Map();
-
-    /** @type {!Multimap<string, !WebInspector.SourceMapTracker>} */
-    this._urlToTrackers = new Multimap();
-    /** @type {!Set<string>} */
-    this._cssURLs = new Set();
-
-    this._eventListeners = [
-        this._workspace.addEventListener(WebInspector.Workspace.Events.UISourceCodeAdded, this._uiSourceCodeAdded, this),
-        this._workspace.addEventListener(WebInspector.Workspace.Events.UISourceCodeRemoved, this._uiSourceCodeRemoved, this),
-        this._workspace.addEventListener(WebInspector.Workspace.Events.WorkingCopyChanged, this._uiSourceCodeChanged, this),
-        this._workspace.addEventListener(WebInspector.Workspace.Events.WorkingCopyCommitted, this._uiSourceCodeChanged, this),
-        this._cssModel.addEventListener(WebInspector.CSSStyleModel.Events.StyleSheetAdded, this._styleSheetAdded, this),
-        this._cssModel.addEventListener(WebInspector.CSSStyleModel.Events.StyleSheetRemoved, this._styleSheetRemoved, this),
-        this._cssModel.addEventListener(WebInspector.CSSStyleModel.Events.StyleSheetChanged, this._styleSheetChanged, this)
-    ];
-}
-
-/**
- * @constructor
- * @param {string} url
- * @param {number} version
- * @param {string} text
- */
-WebInspector.SASSWorkspaceAdapter.ContentResponse = function(url, version, text)
-{
-    this.url = url;
-    this.version = version;
-    this.text = text;
-}
-
-WebInspector.SASSWorkspaceAdapter.prototype = {
-    /**
-     * @param {!WebInspector.SourceMap} sourceMap
-     * @return {!WebInspector.SourceMapTracker}
-     */
-    trackSources: function(sourceMap)
-    {
-        var cssURL = sourceMap.compiledURL();
-        this._cssURLs.add(cssURL);
-
-        var allSources = new Set(sourceMap.sources().concat(cssURL));
-        for (var sourceURL of allSources) {
-            if (this._versions.has(sourceURL))
-                continue;
-            this._versions.set(sourceURL, 1);
-            var promise = new Promise(fulfill => this._awaitingFulfills.set(sourceURL, fulfill));
-            this._awaitingPromises.set(sourceURL, promise);
-            var contentProvider = sourceURL === cssURL ? this._headersForURL(sourceURL).peekLast() : this._sassUISourceCode(sourceURL);
-            if (contentProvider)
-                this._contentProviderAdded(sourceURL);
-        }
-
-        var tracker = new WebInspector.SourceMapTracker(this, sourceMap);
-        for (var sourceURL of tracker.allURLs())
-            this._urlToTrackers.set(sourceURL, tracker);
-        return tracker;
-    },
-
-    /**
-     * @param {!WebInspector.SourceMapTracker} tracker
-     */
-    _stopTrackSources: function(tracker)
-    {
-        for (var sourceURL of tracker.allURLs()) {
-            this._urlToTrackers.remove(sourceURL, tracker);
-            if (!this._urlToTrackers.has(sourceURL)) {
-                this._awaitingFulfills.get(sourceURL).call(null, false);
-                this._awaitingFulfills.delete(sourceURL);
-                this._awaitingPromises.delete(sourceURL);
-                this._versions.delete(sourceURL);
-                this._cssURLs.delete(sourceURL);
-            }
-        }
-    },
-
-    /**
-     * @param {string} url
-     * @return {?WebInspector.UISourceCode}
-     */
-    _sassUISourceCode: function(url)
-    {
-        return this._networkMapping.uiSourceCodeForURLForAnyTarget(url);
-    },
-
-    /**
-     * @param {string} url
-     * @return {!Array<!WebInspector.CSSStyleSheetHeader>}
-     */
-    _headersForURL: function(url)
-    {
-        return this._cssModel.styleSheetIdsForURL(url)
-            .map(styleSheetId => this._cssModel.styleSheetHeaderForId(styleSheetId));
-    },
-
-    /**
-     * @param {string} url
-     */
-    _contentProviderAdded: function(url)
-    {
-        this._awaitingFulfills.get(url).call(null, true);
-    },
-
-    /**
-     * @param {string} url
-     */
-    _contentProviderRemoved: function(url)
-    {
-        var trackers = new Set(this._urlToTrackers.get(url));
-        for (var tracker of trackers)
-            tracker.dispose();
-    },
-
-    /**
-     * @param {string} url
-     * @return {boolean}
-     */
-    _isSASSURL: function(url)
-    {
-        return this._versions.has(url) && !this._cssURLs.has(url);
-    },
-
-    /**
-     * @param {!WebInspector.Event} event
-     */
-    _uiSourceCodeAdded: function(event)
-    {
-        var uiSourceCode = /** @type {!WebInspector.UISourceCode} */(event.data);
-        var url = this._networkMapping.networkURL(uiSourceCode);
-        if (!this._isSASSURL(url))
-            return;
-        this._contentProviderAdded(url);
-    },
-
-    /**
-     * @param {!WebInspector.Event} event
-     */
-    _uiSourceCodeRemoved: function(event)
-    {
-        var uiSourceCode = /** @type {!WebInspector.UISourceCode} */(event.data);
-        var url = this._networkMapping.networkURL(uiSourceCode);
-        if (!this._isSASSURL(url))
-            return;
-        this._contentProviderRemoved(url);
-    },
-
-    /**
-     * @param {!WebInspector.Event} event
-     */
-    _styleSheetAdded: function(event)
-    {
-        var styleSheetHeader = /** @type {!WebInspector.CSSStyleSheetHeader} */(event.data);
-        var url = styleSheetHeader.sourceURL;
-        if (!this._cssURLs.has(url))
-            return;
-        this._contentProviderAdded(url);
-    },
-
-    /**
-     * @param {!WebInspector.Event} event
-     */
-    _styleSheetRemoved: function(event)
-    {
-        var styleSheetHeader = /** @type {!WebInspector.CSSStyleSheetHeader} */(event.data);
-        var url = styleSheetHeader.sourceURL;
-        if (!this._cssURLs.has(url))
-            return;
-        var headers = this._headersForURL(url);
-        if (headers.length)
-            return;
-        this._contentProviderRemoved(url);
-    },
-
-    /**
-     * @param {!WebInspector.Event} event
-     */
-    _uiSourceCodeChanged: function(event)
-    {
-        var uiSourceCode = /** @type {!WebInspector.UISourceCode} */(event.data.uiSourceCode);
-        var url = this._networkMapping.networkURL(uiSourceCode);
-        if (!this._isSASSURL(url))
-            return;
-        this._newContentAvailable(url);
-    },
-
-    /**
-     * @param {!WebInspector.Event} event
-     */
-    _styleSheetChanged: function(event)
-    {
-        var styleSheetId = /** @type {!CSSAgent.StyleSheetId} */(event.data.styleSheetId);
-        var styleSheetHeader = this._cssModel.styleSheetHeaderForId(styleSheetId);
-        var url = styleSheetHeader.sourceURL;
-        if (!this._cssURLs.has(url))
-            return;
-        this._newContentAvailable(url);
-    },
-
-    /**
-     * @param {string} url
-     */
-    _newContentAvailable: function(url)
-    {
-        console.assert(this._versions.has(url), "The '" + url + "' is not tracked.")
-        var newVersion = this._versions.get(url) + 1;
-        this._versions.set(url, newVersion);
-        for (var tracker of this._urlToTrackers.get(url))
-            tracker._newContentAvailable(url, newVersion);
-    },
-
-    /**
-     * @param {string} url
-     * @return {number}
-     */
-    _urlVersion: function(url)
-    {
-        var version = this._versions.get(url);
-        console.assert(version, "The '" + url + "' is not tracked.")
-        return version || 0;
-    },
-
-    /**
-     * @param {string} url
-     * @return {!Promise<?WebInspector.SASSWorkspaceAdapter.ContentResponse>}
-     */
-    _getContent: function(url)
-    {
-        console.assert(this._awaitingPromises.has(url), "The '" + url + "' is not tracked.")
-        return this._awaitingPromises.get(url)
-            .then(onContentProviderResolved.bind(this));
-
-        /**
-         * @param {boolean} success
-         * @return {!Promise<?WebInspector.SASSWorkspaceAdapter.ContentResponse>}
-         * @this {WebInspector.SASSWorkspaceAdapter}
-         */
-        function onContentProviderResolved(success)
-        {
-            if (!success)
-                return Promise.resolve(/** @type {?WebInspector.SASSWorkspaceAdapter.ContentResponse} */(null));
-            var contentProvider = this._cssURLs.has(url) ? this._headersForURL(url).peekLast() : this._sassUISourceCode(url);
-            if (!contentProvider)
-                return Promise.resolve(/** @type {?WebInspector.SASSWorkspaceAdapter.ContentResponse} */(null));
-            return contentProvider.requestContent()
-                .then(text => new WebInspector.SASSWorkspaceAdapter.ContentResponse(url, /** @type {number} */(this._versions.get(url)), text || ""));
-        }
-    },
-
-    /**
-     * @param {string} url
-     * @param {string} text
-     * @return {?WebInspector.SASSWorkspaceAdapter.ContentResponse}
-     */
-    _setSASSText: function(url, text)
-    {
-        console.assert(this._isSASSURL(url), "The url '" + url + "' should be a tracked SASS url");
-        var uiSourceCode = this._sassUISourceCode(url);
-        if (!uiSourceCode)
-            return null;
-        setImmediate(() => uiSourceCode.addRevision(text));
-        var futureVersion = this._versions.get(url) + 1;
-        return new WebInspector.SASSWorkspaceAdapter.ContentResponse(url, futureVersion, text);
-    },
-
-    /**
-     * @param {string} url
-     * @param {string} text
-     * @param {!Array<!WebInspector.SourceEdit>} cssEdits
-     * @return {?WebInspector.SASSWorkspaceAdapter.ContentResponse}
-     */
-    _setCSSText: function(url, text, cssEdits)
-    {
-        console.assert(this._cssURLs.has(url), "The url '" + url + "' should be a tracked CSS url");
-        var headers = this._headersForURL(url);
-        if (!headers.length)
-            return null;
-        for (var i = 0; i < headers.length; ++i)
-            this._cssModel.setStyleSheetText(headers[i].id, text, true);
-        for (var i = cssEdits.length - 1; i >= 0; --i) {
-            var edit = cssEdits[i];
-            var oldRange = edit.oldRange;
-            var newRange = edit.newRange();
-            for (var j = 0; j < headers.length; ++j) {
-                this._cssModel.dispatchEventToListeners(WebInspector.CSSStyleModel.Events.ExternalRangeEdit, {
-                    styleSheetId: headers[j].id,
-                    oldRange: oldRange,
-                    newRange: newRange
-                });
-            }
-        }
-        var futureVersion = this._versions.get(url) + headers.length;
-        return new WebInspector.SASSWorkspaceAdapter.ContentResponse(url, futureVersion, text);
-    }
-}
-
-/**
- * @constructor
- * @extends {WebInspector.Object}
- * @param {!WebInspector.SASSWorkspaceAdapter} adapter
- * @param {!WebInspector.SourceMap} sourceMap
- */
-WebInspector.SourceMapTracker = function(adapter, sourceMap)
-{
-    WebInspector.Object.call(this);
-    this._adapter = adapter;
-    this._sourceMap = sourceMap;
-    this._cssURL = sourceMap.compiledURL();
-    this._sassURLs = sourceMap.sources().slice();
-    this._allURLs = this._sassURLs.concat(this._cssURL);
-    this._terminated = false;
-    this._versions = new Map();
-    for (var url of this._allURLs)
-        this._versions.set(url, adapter._urlVersion(url));
-}
-
-/** @enum {string} */
-WebInspector.SourceMapTracker.Events = {
-    SourceChanged: "SourceChanged",
-    TrackingStopped: "TrackingStopped"
-}
-
-WebInspector.SourceMapTracker.prototype = {
-    /**
-     * @return {!WebInspector.SourceMap}
-     */
-    sourceMap: function()
-    {
-        return this._sourceMap;
-    },
-
-    /**
-     * @return {!Array<string>}
-     */
-    allURLs: function()
-    {
-        return this._allURLs;
-    },
-
-    /**
-     * @return {string}
-     */
-    cssURL: function()
-    {
-        return this._cssURL;
-    },
-
-    /**
-     * @return {!Array<string>}
-     */
-    sassURLs: function()
-    {
-        return this._sassURLs;
-    },
-
-    /**
-     * @return {boolean}
-     */
-    isOutdated: function()
-    {
-        if (this._terminated)
-            return true;
-        for (var url of this._allURLs) {
-            if (this._adapter._urlVersion(url) > this._versions.get(url))
-                return true;
-        }
-        return false;
-    },
-
-    /**
-     * @param {string} text
-     * @param {!Array<!WebInspector.SourceEdit>} edits
-     * @return {boolean}
-     */
-    setCSSText: function(text, edits)
-    {
-        if (this._terminated || this.isOutdated())
-            return false;
-        var result = this._adapter._setCSSText(this._cssURL, text, edits);
-        this._handleContentResponse(result);
-        return !!result;
-    },
-
-    /**
-     * @param {string} url
-     * @param {string} text
-     * @return {boolean}
-     */
-    setSASSText: function(url, text)
-    {
-        if (this._terminated || this.isOutdated())
-            return false;
-        var result = this._adapter._setSASSText(url, text);
-        this._handleContentResponse(result);
-        return !!result;
-    },
-
-    /**
-     * @param {?WebInspector.SASSWorkspaceAdapter.ContentResponse} contentResponse
-     * @return {?string}
-     */
-    _handleContentResponse: function(contentResponse)
-    {
-        if (!contentResponse)
-            return null;
-        this._versions.set(contentResponse.url, contentResponse.version);
-        return contentResponse.text;
-    },
-
-    /**
-     * @param {string} url
-     * @return {!Promise<string>}
-     */
-    content: function(url)
-    {
-        return this._adapter._getContent(url)
-            .then(this._handleContentResponse.bind(this))
-            .then(text => text || "");
-    },
-
-    dispose: function()
-    {
-        if (this._terminated)
-            return;
-        this._terminated = true;
-        this._adapter._stopTrackSources(this);
-        this.dispatchEventToListeners(WebInspector.SourceMapTracker.Events.TrackingStopped);
-    },
-
-    /**
-     * @param {string} url
-     * @param {number} newVersion
-     */
-    _newContentAvailable: function(url, newVersion)
-    {
-        if (this._versions.get(url) < newVersion)
-            this.dispatchEventToListeners(WebInspector.SourceMapTracker.Events.SourceChanged, url);
-    },
-
-    __proto__: WebInspector.Object.prototype
-}
diff --git a/third_party/WebKit/Source/devtools/front_end/sass/module.json b/third_party/WebKit/Source/devtools/front_end/sass/module.json
index d4704ba..59c052a 100644
--- a/third_party/WebKit/Source/devtools/front_end/sass/module.json
+++ b/third_party/WebKit/Source/devtools/front_end/sass/module.json
@@ -1,8 +1,8 @@
 {
-    "dependencies": ["platform", "common", "diff", "sdk", "workspace", "bindings"],
+    "dependencies": ["platform", "common", "diff", "sdk"],
     "scripts": [
         "SASSSupport.js",
-        "SASSWorkspaceAdapter.js",
+        "ASTService.js",
         "SASSLiveSourceMap.js"
     ]
 }
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/CSSParser.js b/third_party/WebKit/Source/devtools/front_end/sdk/CSSParser.js
index 6337682..0cafa6f 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/CSSParser.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/CSSParser.js
@@ -66,6 +66,7 @@ WebInspector.CSSParser.prototype = {
         if (this._worker) {
             this._worker.terminate();
             delete this._worker;
+            this._runFinishedCallback([]);
         }
     },
 
@@ -115,8 +116,18 @@ WebInspector.CSSParser.prototype = {
     _onFinishedParsing: function()
     {
         this._unlock();
-        if (this._finishedCallback)
-            this._finishedCallback(this._rules);
+        this._runFinishedCallback(this._rules);
+    },
+
+    /**
+     * @param {!Array<!WebInspector.CSSRule>} rules
+     */
+    _runFinishedCallback: function(rules)
+    {
+        var callback = this._finishedCallback;
+        delete this._finishedCallback;
+        if (callback)
+            callback.call(null, rules);
     },
 
     __proto__: WebInspector.Object.prototype,
@@ -165,3 +176,76 @@ WebInspector.CSSParser.Property = function()
     /** @type {(boolean|undefined)} */
     this.disabled;
 }
+
+/**
+ * @constructor
+ */
+WebInspector.CSSParserService = function()
+{
+    this._cssParser = null;
+    this._cssRequests = [];
+    this._terminated = false;
+}
+
+WebInspector.CSSParserService.prototype = {
+    /**
+     * @param {string} text
+     * @return {!Promise<!Array.<!WebInspector.CSSParser.Rule>>}
+     */
+    parseCSS: function(text)
+    {
+        console.assert(!this._terminated, "Illegal call parseCSS on terminated CSSParserService.");
+        if (!this._cssParser)
+            this._cssParser = new WebInspector.CSSParser();
+        var request = new WebInspector.CSSParserService.ParseRequest(text);
+        this._cssRequests.push(request);
+        this._maybeParseCSS();
+        return request.parsedPromise;
+    },
+
+    _maybeParseCSS: function()
+    {
+        if (this._terminated || this._isParsingCSS || !this._cssRequests.length)
+            return;
+        this._isParsingCSS = true;
+        var request = this._cssRequests.shift();
+        this._cssParser.parsePromise(request.text)
+            .catchException(/** @type {!Array.<!WebInspector.CSSParser.Rule>} */([]))
+            .then(onCSSParsed.bind(this));
+
+        /**
+         * @param {!Array.<!WebInspector.CSSParser.Rule>} rules
+         * @this {WebInspector.CSSParserService}
+         */
+        function onCSSParsed(rules)
+        {
+            request.parsedCallback.call(null, rules);
+            this._isParsingCSS = false;
+            this._maybeParseCSS();
+        }
+    },
+
+    dispose: function()
+    {
+        if (this._terminated)
+            return;
+        this._terminated = true;
+        if (this._cssParser)
+            this._cssParser.dispose();
+        for (var request of this._cssRequests)
+            request.parsedCallback.call(null, /** @type {!Array.<!WebInspector.CSSParser.Rule>} */([]));
+        this._cssRequests = [];
+    },
+}
+
+/**
+ * @constructor
+ * @param {string} text
+ */
+WebInspector.CSSParserService.ParseRequest = function(text)
+{
+    this.text = text;
+    /** @type {function(!Array.<!WebInspector.CSSParser.Rule>)} */
+    this.parsedCallback;
+    this.parsedPromise = new Promise(fulfill => this.parsedCallback = fulfill);
+}
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleModel.js b/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleModel.js
index ce5548d..cc46da3 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleModel.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleModel.js
@@ -70,8 +70,7 @@ WebInspector.CSSStyleModel.Events = {
     PseudoStateForced: "PseudoStateForced",
     StyleSheetAdded: "StyleSheetAdded",
     StyleSheetChanged: "StyleSheetChanged",
-    StyleSheetRemoved: "StyleSheetRemoved",
-    ExternalRangeEdit: "ExternalRangeEdit"
+    StyleSheetRemoved: "StyleSheetRemoved"
 }
 
 WebInspector.CSSStyleModel.MediaTypes = ["all", "braille", "embossed", "handheld", "print", "projection", "screen", "speech", "tty", "tv"];