Tie scroll anchoring adjustments to frame lifecycle instead of layout.

third_party/WebKit/Source/web/tests/VisualViewportTest.cpp

Index: third_party/WebKit/Source/web/tests/VisualViewportTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/VisualViewportTest.cpp b/third_party/WebKit/Source/web/tests/VisualViewportTest.cpp
index 6a06e377bfc6ef12e09ece72292c01455913fcd9..f58086a5ba76ae935ab77a6f8d9e8504a2b76d09 100644
--- a/third_party/WebKit/Source/web/tests/VisualViewportTest.cpp
+++ b/third_party/WebKit/Source/web/tests/VisualViewportTest.cpp
@@ -1997,6 +1997,7 @@ TEST_P(ParameterizedVisualViewportTest, ResizeWithScrollAnchoring) {
   FrameView& frameView = *webViewImpl()->mainFrameImpl()->frameView();
   frameView.layoutViewportScrollableArea()->setScrollOffset(
       ScrollOffset(700, 500), ProgrammaticScroll);
+  webViewImpl()->updateAllLifecyclePhases();

[ymalik, 2016/10/13 13:05:40]

Why did we need to add this?

[skobes, 2016/10/13 17:21:37]

The programmatic scroll clears the anchor node.  If we don't finish the frame
here, the layout that happens during WebViewImpl::resize won't compute a new
one.

I think that's the correct behavior - if the page sets scrollTop in the same
frame as the anchor node moves, the programmatic scroll should "win".

[ymalik, 2016/10/13 17:53:19]

Acknowledged.

 
   webViewImpl()->resize(IntSize(800, 300));
   EXPECT_SIZE_EQ(ScrollOffset(700, 200),