Added showing slow scroll rectangles in Layers panel.

LayoutTests/http/tests/inspector/layers-test.js

Index: LayoutTests/http/tests/inspector/layers-test.js
diff --git a/LayoutTests/http/tests/inspector/layers-test.js b/LayoutTests/http/tests/inspector/layers-test.js
index 6e019d7e1d9a2884200045236e0632c85e40c475..8b82cae3b59abcec4efe3ccbe64f2a2ea00ff3b9 100644
--- a/LayoutTests/http/tests/inspector/layers-test.js
+++ b/LayoutTests/http/tests/inspector/layers-test.js
@@ -101,4 +101,24 @@ function initialize_LayerTreeTests()
             callback();
         }
     }
+
+    InspectorTest.dumpViewScrollRect = function(element)
+    {
+        InspectorTest.addObject(element.__scrollRect, {layerId: "formatAsTypeName"}, "", "scrollRect: ");
+    }
+
+    InspectorTest.dumpViewScrollRects = function()
+    {
+        InspectorTest.addResult("View elements dump");
+        var root = WebInspector.panel("layers")._layers3DView._rotatingContainerElement;
+        Array.prototype.forEach.call(root.querySelectorAll('.scroll-rect'), function(element) {

[caseq, 2014/02/26 11:21:10]

nit: use InspectorTest.dumpViewScrollRect.bind(InspectorTest) instead of
function literal.

[malch, 2014/02/26 11:43:36]

Done.

+            InspectorTest.dumpViewScrollRect(element);
+        });
+    }
+
+    InspectorTest.dumpModelScrollRects = function()
+    {
+        InspectorTest.addResult("Model elements dump");
+        InspectorTest.addObject(InspectorTest._layerTreeModel._scrollRectsByLayerId, {layerId: "formatAsTypeName"}, "", "scrollRectsByLayerId: ");
+    }
 }