From c8d918efa99edfb8d6a751cea96563cd409f4d88 Mon Sep 17 00:00:00 2001
From: Ojan Vafai <ojan@chromium.org>
Date: Wed, 15 Apr 2015 11:08:32 -0700
Subject: [PATCH] Make changing your layout manager work.

If your layout manager changes, then you need to setNeedsLayout,
otherwise the next frame doesn't even get scheduled. We already
correctly handle going from not having layout to having one or
vice versa by doing the more drastic reattaching since that
requires changing your actual render class.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1060013005
---
 engine/core/dom/Element.cpp |  2 ++
 tests/layout/custom.sky     | 45 ++++++++++++++++++++++---------------
 2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/engine/core/dom/Element.cpp b/engine/core/dom/Element.cpp
index 8537adb6d5e..c3b6a981518 100644
--- a/engine/core/dom/Element.cpp
+++ b/engine/core/dom/Element.cpp
@@ -971,6 +971,8 @@ void Element::setLayoutManager(PassOwnPtr<LayoutCallback> callback)
         // those are all tied to changes to the RenderStyle.
         markAncestorsWithChildNeedsStyleRecalc();
         detach();
+    } else if (callback.get() != m_layoutManager) {
+        setNeedsLayout();
     }
     m_layoutManager = callback;
 }
diff --git a/tests/layout/custom.sky b/tests/layout/custom.sky
index 586dd26fe9d..e212a6e7a01 100644
--- a/tests/layout/custom.sky
+++ b/tests/layout/custom.sky
@@ -84,30 +84,39 @@ void main() {
         expect(secondChild.offsetWidth, equals(150));
         assertNonChangingValues();
 
-        parent.setLayoutManager(null);
+        parent.setLayoutManager(() {
+          parent.width = 250.0;
+        });
 
         window.requestAnimationFrame((_) {
-          expect(parent.offsetWidth, equals(300));
-          expect(parent.offsetHeight, equals(50));
-          expect(parent.offsetTop, equals(0));
-          expect(parent.offsetLeft, equals(0));
+          expect(parent.offsetWidth, equals(250));
+          assertNonChangingValues();
 
-          expect(firstChild.offsetWidth, equals(300));
-          expect(firstChild.offsetHeight, equals(25));
-          expect(firstChild.offsetTop, equals(0));
-          expect(firstChild.offsetLeft, equals(0));
+          parent.setLayoutManager(null);
 
-          expect(secondChild.offsetWidth, equals(300));
-          expect(secondChild.offsetHeight, equals(25));
-          expect(secondChild.offsetTop, equals(25));
-          expect(secondChild.offsetLeft, equals(0));
+          window.requestAnimationFrame((_) {
+            expect(parent.offsetWidth, equals(300));
+            expect(parent.offsetHeight, equals(50));
+            expect(parent.offsetTop, equals(0));
+            expect(parent.offsetLeft, equals(0));
 
-          expect(grandChild.offsetWidth, equals(25));
-          expect(grandChild.offsetHeight, equals(25));
-          expect(grandChild.offsetTop, equals(0));
-          expect(grandChild.offsetLeft, equals(0));
+            expect(firstChild.offsetWidth, equals(300));
+            expect(firstChild.offsetHeight, equals(25));
+            expect(firstChild.offsetTop, equals(0));
+            expect(firstChild.offsetLeft, equals(0));
 
-          completer.complete();
+            expect(secondChild.offsetWidth, equals(300));
+            expect(secondChild.offsetHeight, equals(25));
+            expect(secondChild.offsetTop, equals(25));
+            expect(secondChild.offsetLeft, equals(0));
+
+            expect(grandChild.offsetWidth, equals(25));
+            expect(grandChild.offsetHeight, equals(25));
+            expect(grandChild.offsetTop, equals(0));
+            expect(grandChild.offsetLeft, equals(0));
+
+            completer.complete();
+          });
         });
       });
     });