diff -r 000000000000 -r 6474c204b198 browser/devtools/netmonitor/test/browser_net_autoscroll.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/netmonitor/test/browser_net_autoscroll.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,90 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Bug 863102 - Automatically scroll down upon new network requests.
+ */
+
+function test() {
+  requestLongerTimeout(2);
+  let monitor, debuggee, requestsContainer, scrollTop;
+
+  initNetMonitor(INFINITE_GET_URL).then(([aTab, aDebuggee, aMonitor]) => {
+    monitor = aMonitor;
+    debuggee = aDebuggee;
+    let win = monitor.panelWin;
+    let topNode = win.document.getElementById("requests-menu-contents");
+    requestsContainer = topNode.getElementsByTagName("scrollbox")[0];
+    ok(!!requestsContainer, "Container element exists as expected.");
+  })
+
+  // (1) Check that the scroll position is maintained at the bottom
+  // when the requests overflow the vertical size of the container.
+  .then(() => {
+    return waitForRequestsToOverflowContainer(monitor, requestsContainer);
+  })
+  .then(() => {
+    ok(scrolledToBottom(requestsContainer), "Scrolled to bottom on overflow.");
+  })
+
+  // (2) Now set the scroll position somewhere in the middle and check
+  // that additional requests do not change the scroll position.
+  .then(() => {
+    let children = requestsContainer.childNodes;
+    let middleNode = children.item(children.length / 2);
+    middleNode.scrollIntoView();
+    ok(!scrolledToBottom(requestsContainer), "Not scrolled to bottom.");
+    scrollTop = requestsContainer.scrollTop; // save for comparison later
+    return waitForNetworkEvents(monitor, 8);
+  })
+  .then(() => {
+    is(requestsContainer.scrollTop, scrollTop, "Did not scroll.");
+  })
+
+  // (3) Now set the scroll position back at the bottom and check that
+  // additional requests *do* cause the container to scroll down.
+  .then(() => {
+    requestsContainer.scrollTop = requestsContainer.scrollHeight;
+    ok(scrolledToBottom(requestsContainer), "Set scroll position to bottom.");
+    return waitForNetworkEvents(monitor, 8);
+  })
+  .then(() => {
+    ok(scrolledToBottom(requestsContainer), "Still scrolled to bottom.");
+  })
+
+  // (4) Now select an item in the list and check that additional requests
+  // do not change the scroll position.
+  .then(() => {
+    monitor.panelWin.NetMonitorView.RequestsMenu.selectedIndex = 0;
+    return waitForNetworkEvents(monitor, 8);
+  })
+  .then(() => {
+    is(requestsContainer.scrollTop, 0, "Did not scroll.");
+  })
+
+  // Done; clean up.
+  .then(() => {
+    return teardown(monitor).then(finish);
+  })
+
+  // Handle exceptions in the chain of promises.
+  .then(null, (err) => {
+    ok(false, err);
+    finish();
+  });
+
+  function waitForRequestsToOverflowContainer (aMonitor, aContainer) {
+    return waitForNetworkEvents(aMonitor, 1).then(() => {
+      if (aContainer.scrollHeight > aContainer.clientHeight) {
+        // Wait for some more just for good measure.
+        return waitForNetworkEvents(aMonitor, 8);
+      } else {
+        return waitForRequestsToOverflowContainer(aMonitor, aContainer);
+      }
+    });
+  }
+
+  function scrolledToBottom(aElement) {
+    return aElement.scrollTop + aElement.clientHeight >= aElement.scrollHeight;
+  }
+}