DevTools: improve identifier extraction in SourceMapNamesResolver

third_party/WebKit/Source/devtools/front_end/formatter_worker/FormatterWorker.js

Index: third_party/WebKit/Source/devtools/front_end/formatter_worker/FormatterWorker.js
diff --git a/third_party/WebKit/Source/devtools/front_end/formatter_worker/FormatterWorker.js b/third_party/WebKit/Source/devtools/front_end/formatter_worker/FormatterWorker.js
index 37014ddcfc467fcdfb9099eb1d9ffe47a2fc3e32..2c8fd460578b23d61b7e29c7f08c1b2068a97a12 100644
--- a/third_party/WebKit/Source/devtools/front_end/formatter_worker/FormatterWorker.js
+++ b/third_party/WebKit/Source/devtools/front_end/formatter_worker/FormatterWorker.js
@@ -131,11 +131,11 @@ WebInspector.evaluatableJavaScriptSubstring = function(content)
  */
 WebInspector.javaScriptIdentifiers = function(content)
 {
-    var root = acorn.parse(content, {});
+    var root = acorn.parse(content, { ranges: false, ecmaVersion: 6 });
+
     /** @type {!Array<!ESTree.Node>} */
     var identifiers = [];
-    var functionDeclarationCounter = 0;
-    var walker = new WebInspector.ESTreeWalker(beforeVisit, afterVisit);
+    var walker = new WebInspector.ESTreeWalker(beforeVisit);
 
     /**
      * @param {!ESTree.Node} node
@@ -143,7 +143,7 @@ WebInspector.javaScriptIdentifiers = function(content)
      */
     function isFunction(node)
     {
-        return node.type === "FunctionDeclaration" || node.type === "FunctionExpression";
+        return node.type === "FunctionDeclaration" || node.type === "FunctionExpression" || node.type === "ArrowFunctionExpression";
     }
 
     /**
@@ -151,29 +151,29 @@ WebInspector.javaScriptIdentifiers = function(content)
      */
     function beforeVisit(node)
     {
-        if (isFunction(node))
-            functionDeclarationCounter++;
+        if (isFunction(node)) {
+            if (node.id)
+                identifiers.push(node.id);
+            return WebInspector.ESTreeWalker.SkipSubtree;
+        }
 
-        if (functionDeclarationCounter > 1)
+        if (node.type !== "Identifier")
             return;
 
-        if (isFunction(node) && node.params)
-            identifiers.pushAll(node.params);
-
-        if (node.type === "VariableDeclarator")
-            identifiers.push(/** @type {!ESTree.Node} */(node.id));
+        if (node.parent && node.parent.type === "MemberExpression" && node.parent.property === node && !node.parent.computed)
+            return;
+        identifiers.push(node);
     }
 
-    /**
-     * @param {!ESTree.Node} node
-     */
-    function afterVisit(node)
-    {
-        if (isFunction(node))
-            functionDeclarationCounter--;
+    if (!root || root.type !== "Program" || root.body.length !== 1 || !isFunction(root.body[0])) {
+        postMessage([]);
+        return;
     }
 
-    walker.walk(root);
+    var functionNode = root.body[0];
+    for (var param of functionNode.params)
+        walker.walk(param);
+    walker.walk(functionNode.body);
     var reduced = identifiers.map(id => ({name: id.name, offset: id.start}));
     postMessage(reduced);
 }