[DevTools] Cleanup DOMExtension.js.

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

Index: third_party/WebKit/LayoutTests/http/tests/inspector/layers-test.js
diff --git a/third_party/WebKit/LayoutTests/http/tests/inspector/layers-test.js b/third_party/WebKit/LayoutTests/http/tests/inspector/layers-test.js
index 8792490dce3a25ab8fab2c7b94d02eb8c9b8c132..d2cb26c1ba2d813ea27ccc5c3452152e503ca6f8 100644
--- a/third_party/WebKit/LayoutTests/http/tests/inspector/layers-test.js
+++ b/third_party/WebKit/LayoutTests/http/tests/inspector/layers-test.js
@@ -105,13 +105,19 @@ function initialize_LayerTreeTests()
     InspectorTest.dispatchMouseEvent = function(eventType, button, element, offsetX, offsetY)
     {
         var totalOffset = element.totalOffset();
-        var scrollOffset = element.scrollOffset();
+        var scrollLeft = 0;
+        var scrollTop = 0;
+        for (var parent = element; parent; parent = parent.scrollParent) {

[lushnikov, 2016/10/05 16:03:59]

AFAIU there's no such thing as "scrollParent". So you can safely remove the
"for"-loop

[dgozman, 2016/10/05 17:29:30]

Done.

+            scrollLeft += parent.scrollLeft;
+            scrollTop += parent.scrollTop;
+        }
+
         var eventArguments = {
             bubbles: true,
             cancelable: true,
             view: window,
-            screenX: totalOffset.left - scrollOffset.left + offsetX,
-            screenY: totalOffset.top - scrollOffset.top + offsetY,
+            screenX: totalOffset.left - scrollLeft + offsetX,
+            screenY: totalOffset.top - scrollTop + offsetY,
             clientX: totalOffset.left + offsetX,
             clientY: totalOffset.top + offsetY,
             button: button