DevTools: fix stick to bottom in console viewport

third_party/WebKit/LayoutTests/inspector/console/console-viewport-stick-to-bottom.html

Index: third_party/WebKit/LayoutTests/inspector/console/console-viewport-stick-to-bottom.html
diff --git a/third_party/WebKit/LayoutTests/inspector/console/console-viewport-stick-to-bottom.html b/third_party/WebKit/LayoutTests/inspector/console/console-viewport-stick-to-bottom.html
index fc4901ad831a1b0bd2c44a4d50a6d739d97232a8..a06228eebe40b045814310547c87e249f01b9143 100644
--- a/third_party/WebKit/LayoutTests/inspector/console/console-viewport-stick-to-bottom.html
+++ b/third_party/WebKit/LayoutTests/inspector/console/console-viewport-stick-to-bottom.html
@@ -14,6 +14,7 @@ function populateConsoleWithMessages(count)
 </script>
 
 <script>
+// window.debugTest = true
 
 function test()
 {
@@ -56,27 +57,65 @@ function test()
 
             function onMessagesDumped()
             {
+                // Force a second call to refresh() after a first call within
+                // invalidate() triggers a scroll to bottom event.
                 viewport.invalidate();
-                // Force refresh which has been scheduled via invalidate() method.
                 viewport.refresh();
-                InspectorTest.addResult("Last visible message: " + viewport.lastVisibleIndex());
+
+                logIsAtBottom();
                 next();
             }
         },
 
-        function testManualScrollDoesNotStickToBottom(next)
-        {
-            const manualScrollValue = 3;
-            var initialScrollTop = viewport.element.scrollTop;
-            viewport.element.scrollTop = initialScrollTop - manualScrollValue;
-            viewport.refresh();
-            var newScrollTop = viewport.element.scrollTop;
-            var isScrollPreserved = initialScrollTop - newScrollTop === manualScrollValue;
-            InspectorTest.addResult("Scroll preserved: " + isScrollPreserved);
-            next();
-        },
+        // function testEscShouldNotJumpToBottom(next)
+        // {
+        //     eventSender.keyDown('Escape');
+        //     InspectorTest.addSniffer(WebInspector.ConsoleView.prototype, "_scrollUpdatedByUserForTest", function () {
+        //         logIsAtBottom();
+        //         next();
+        //     });
+        // },
+
+        // function testTypingShouldJumpToBottom(next)
+        // {
+        //     eventSender.keyDown('a');
+        //     InspectorTest.addSniffer(WebInspector.ConsoleView.prototype, "_scrollUpdatedByUserForTest", function () {
+        //         logIsAtBottom();
+        //         next();
+        //     });
+        // },
+
+        // function testSmoothScrollDoesNotStickToBottom(next)
+        // {
+        //     eventSender.keyDown('PageUp');
+        //     InspectorTest.addSniffer(WebInspector.ConsoleView.prototype, "_scrollUpdatedByUserForTest", function () {
+        //         logIsAtBottom();
+        //         next();
+        //     });
+        // },
+
+        function testViewportMuationsShouldPreserveStickToBottom(next) {
+            InspectorTest.addSniffer(WebInspector.ViewportControl.prototype, "refresh", onRefresh);
+            viewport._contentElement.children[1].innerText = "foo\n\n\n\nbar";
+
+            function onRefresh()
+            {
+                logIsAtBottom();
+                next();
+            }
+        }
     ];
 
+    function logIsAtBottom(distance)
+    {
+        var dist = viewport.element.scrollHeight - (viewport.element.scrollTop + viewport.element.clientHeight);
+        if (distance)
+            InspectorTest.addResult("Distance from bottom: " + dist);
+        else
+            InspectorTest.addResult("Is at bottom: " + viewport.element.isScrolledToBottom() + ", should stick: " + viewport.stickToBottom());
+    }
+
+
     function logMessagesToConsole(count, callback)
     {
         var awaitingMessagesCount = count;