DevTools: Add support for inspector layout tests. Step 1.

webkit/glue/devtools/js/devtools.js

Index: webkit/glue/devtools/js/devtools.js
diff --git a/webkit/glue/devtools/js/devtools.js b/webkit/glue/devtools/js/devtools.js
index 494b600b5c5e5d76b1f8bfeae0a7e95eeebb39c1..5c167cdaf578f57207d401f3528d59fd629a1ac8 100644
--- a/webkit/glue/devtools/js/devtools.js
+++ b/webkit/glue/devtools/js/devtools.js
@@ -483,6 +483,23 @@ WebInspector.ElementsPanel.prototype._nodeSearchButtonClicked = function(
 })();
 
 
+// We need to have a place for postponed tasks
+// which should be executed when all the messages between agent and frontend
+// are processed.
+
+WebInspector.runAfterPendingDispatchesQueue = [];
+
+WebInspector.runAfterPendingDispatches = function(callback) { 
+  this.runAfterPendingDispatchesQueue.push(callback); 
+};
+
+WebInspector.queuesAreEmpty = function() {
+  var copy = this.runAfterPendingDispatchesQueue.slice();
+  this.runAfterPendingDispatchesQueue = [];
+  for (var i = 0; i < copy.length; ++i) 
+    copy[i].call(this);
+};
+
 (function() {
 var originalAddToFrame = InspectorFrontendHost.addResourceSourceToFrame;
 InspectorFrontendHost.addResourceSourceToFrame = function(identifier, element) {