Move viewport actions into an ApplyScroll callback.

third_party/WebKit/Source/core/layout/LayoutView.cpp

Index: third_party/WebKit/Source/core/layout/LayoutView.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutView.cpp b/third_party/WebKit/Source/core/layout/LayoutView.cpp
index 6134b5c08ff7808aa552eda99792ae1ea266c4a1..b39d631e4bd9f9b6988e09d6dd504e8a4b2d64b3 100644
--- a/third_party/WebKit/Source/core/layout/LayoutView.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutView.cpp
@@ -1032,10 +1032,16 @@ bool LayoutView::allowsOverflowClip() const
 
 ScrollResult LayoutView::scroll(ScrollGranularity granularity, const FloatSize& delta)
 {
+    // TODO(bokan): This should never get called on the main frame but it
+    // currently does via the Windows pan scrolling path. That should go through
+    // a more normalized EventHandler-like scrolling path and we should
+    // ASSERT(!frame()->isMainFrame()) here. All main frame scrolling should
+    // be handled by the ViewportScrollCallback.
+
     if (!frameView())
-        return ScrollResult();
+        return ScrollResult(false, false, delta.width(), delta.height());
 
-    return frame()->applyScrollDelta(granularity, delta, false);
+    return frameView()->getScrollableArea()->userScroll(granularity, delta);
 }
 
 } // namespace blink