Enable message delivering in inspector-protocol tests when on pause

LayoutTests/inspector-protocol/layers/layers-for-node.html

Index: LayoutTests/inspector-protocol/layers/layers-for-node.html
diff --git a/LayoutTests/inspector-protocol/layers/layers-for-node.html b/LayoutTests/inspector-protocol/layers/layers-for-node.html
index 8d579543b217895536a2b745e1d872ebbbc9dae5..5f4924ff5dffe9726a7cf6b8ade249c048fa838f 100644
--- a/LayoutTests/inspector-protocol/layers/layers-for-node.html
+++ b/LayoutTests/inspector-protocol/layers/layers-for-node.html
@@ -39,7 +39,7 @@ function test()
             name: "Get the Document",
             command: "DOM.getDocument",
             parameters: {},
-            callback: getInitialLayerTree
+            callback: makeDeferredCallback(getInitialLayerTree)
         });
     };
     
@@ -64,7 +64,7 @@ function test()
             name: "Message the page to add a new composited layer",
             command: "Runtime.evaluate",
             parameters: {"expression": "addCompositedLayer()"},
-            callback: getModifiedLayerTree
+            callback: makeDeferredCallback(getModifiedLayerTree)
         });
     };
 
@@ -78,8 +78,6 @@ function test()
         });
     };
 
-    var layerCount = 0;

[Peter.Rybin, 2013/07/10 23:33:58]

Unused variable.

-
     function gotModifiedLayerTree(result)
     {
         dumpLayers(result.layers);
@@ -174,6 +172,15 @@ function test()
             test.callback(messageObject.result);
         });
     };
+    
+    // Makes next step to wait half a second to let backend do its asynchronous processing.

[Peter.Rybin, 2013/07/10 23:33:58]

Backend updates layers by timer, that provokes some race conditions in this
test. With a new message dispatcher, debugger messages start to win the race.

+    function makeDeferredCallback(callback)
+    {
+        return function(result)
+        {
+            setTimeout(callback.bind(this, result), 500);
+        };
+    }
 
     function assert(name, actual, expected)
     {