[DevTools] Simplified DebuggerScript._buildScopeObject

third_party/WebKit/Source/platform/v8_inspector/DebuggerScript.js

Index: third_party/WebKit/Source/platform/v8_inspector/DebuggerScript.js
diff --git a/third_party/WebKit/Source/platform/v8_inspector/DebuggerScript.js b/third_party/WebKit/Source/platform/v8_inspector/DebuggerScript.js
index 85d214e06efad6011204e3e9974bf4fca7dea040..c6d0ae0d86c40fb8ff19b5f6f718374e5dde8765 100644
--- a/third_party/WebKit/Source/platform/v8_inspector/DebuggerScript.js
+++ b/third_party/WebKit/Source/platform/v8_inspector/DebuggerScript.js
@@ -395,9 +395,6 @@ DebuggerScript.getBreakpointNumbers = function(eventData)
     return numbers;
 }
 
-// NOTE: This function is performance critical, as it can be run on every
-// statement that generates an async event (like addEventListener) to support
-// asynchronous call stacks. Thus, when possible, initialize the data lazily.
 /**
  * @param {!FrameMirror} frameMirror
  * @return {!JavaScriptCallFrame}
@@ -666,36 +663,13 @@ DebuggerScript._frameMirrorToJSCallFrame = function(frameMirror)
  */
 DebuggerScript._buildScopeObject = function(scopeType, scopeObject)
 {
-    var result;
-    switch (scopeType) {
-    case ScopeType.Local:
-    case ScopeType.Closure:
-    case ScopeType.Catch:
-    case ScopeType.Block:
-    case ScopeType.Script:
-        // For transient objects we create a "persistent" copy that contains
-        // the same properties.
-        // Reset scope object prototype to null so that the proto properties
-        // don't appear in the local scope section.
-        var properties = /** @type {!ObjectMirror} */(MakeMirror(scopeObject, true /* transient */)).properties();
-        // Almost always Script scope will be empty, so just filter out that noise.
-        // Also drop empty Block scopes, should we get any.
-        if (!properties.length && (scopeType === ScopeType.Script || scopeType === ScopeType.Block))
-            break;
-        result = { __proto__: null };
-        for (var j = 0; j < properties.length; j++) {
-            var name = properties[j].name();
-            if (name.length === 0 || name.charAt(0) === ".")
-                continue; // Skip internal variables like ".arguments" and variables with empty name
-            result[name] = properties[j].value_;
-        }
-        break;
-    case ScopeType.Global:
-    case ScopeType.With:
-        result = scopeObject;
-        break;
+    // Almost always Script scope will be empty, so just filter out that noise.
+    // Also drop empty Block scopes, should we get any.
+    if (scopeType === ScopeType.Script || scopeType === ScopeType.Block) {
+        if (Object.getOwnPropertyNames(scopeObject).length === 0)
+            return undefined;
     }
-    return result;
+    return scopeObject;
 }
 
 // We never resolve Mirror by its handle so to avoid memory leaks caused by Mirrors in the cache we disable it.