DevTools: Convert inspector-unit tests to use reusable test harness

third_party/WebKit/LayoutTests/http/tests/inspector-unit/static-viewport-control.js

+TestRunner.addResult("This tests if the StaticViewportControl works properly.");
+
+var items = [];
+var heights = [];
+for (var i = 0; i < 100; i++){
+    items[i] = document.createElement("div");
+    items[i].style.height = (heights[i] = (i % 4) ? 50 : 28) + "px";
+    items[i].textContent = i;
+}
+var viewport = new UI.StaticViewportControl({
+    fastItemHeight: i => heights[i],
+    itemCount: _ => items.length,
+    itemElement: i => items[i]
+});
+viewport.element.style.height = "300px";
+UI.inspectorView.element.appendChild(viewport.element);
+
+viewport.refresh();
+dumpViewport();
+
+viewport.forceScrollItemToBeFirst(26);
+dumpViewport();
+
+viewport.scrollItemIntoView(33);
+dumpViewport();
+
+viewport.scrollItemIntoView(30);
+dumpViewport();
+
+viewport.forceScrollItemToBeFirst(30);
+dumpViewport();
+
+viewport.forceScrollItemToBeLast(88);
+dumpViewport();
+
+for (var i = 0; i < 100; i++)
+    items[i].style.height = (heights[i] = (i % 2) ? 55 : 63) + "px";
+viewport.refresh();
+viewport.forceScrollItemToBeLast(88);
+dumpViewport();
+
+TestRunner.completeTest();
+
+function dumpViewport()
+{
+    TestRunner.addResult("First:" + viewport.firstVisibleIndex());
+    TestRunner.addResult("Last:" + viewport.lastVisibleIndex());
+    TestRunner.addResult("Active Items:" + viewport._innerElement.children.length);
+    TestRunner.addResult("");
+}