LayoutBox::scrollRectToVisible doesn't respect overflow:hidden property.

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

Index: third_party/WebKit/Source/core/layout/LayoutBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.cpp b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
index 0272e0ac8552e1f0090d5ad84d5e849afad17c0b..c310ac2346f8c2fdf7649234c7ec754ee27e64d9 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -503,8 +503,9 @@ static bool isDisallowedAutoscroll(HTMLFrameOwnerElement* ownerElement, FrameVie
     return false;
 }
 
-void LayoutBox::scrollRectToVisible(const LayoutRect& rect, const ScrollAlignment& alignX, const ScrollAlignment& alignY)
+void LayoutBox::scrollRectToVisible(const LayoutRect& rect, const ScrollAlignment& alignX, const ScrollAlignment& alignY, ScrollType scrollType)
 {
+    ASSERT(scrollType == ProgrammaticScroll || scrollType == UserScroll);
     // Presumably the same issue as in setScrollTop. See crbug.com/343132.
     DisableCompositingQueryAsserts disabler;
 
@@ -520,12 +521,12 @@ void LayoutBox::scrollRectToVisible(const LayoutRect& rect, const ScrollAlignmen
     if (hasOverflowClip() && !restrictedByLineClamp) {
         // Don't scroll to reveal an overflow layer that is restricted by the -webkit-line-clamp property.
         // This will prevent us from revealing text hidden by the slider in Safari RSS.
-        newRect = layer()->scrollableArea()->scrollIntoView(rect, alignX, alignY);
+        newRect = layer()->scrollableArea()->scrollIntoView(rect, alignX, alignY, scrollType);
     } else if (!parentBox && canBeProgramaticallyScrolled()) {
         if (FrameView* frameView = this->frameView()) {
             HTMLFrameOwnerElement* ownerElement = document().ownerElement();
             if (!isDisallowedAutoscroll(ownerElement, frameView)) {
-                frameView->scrollableArea()->scrollIntoView(rect, alignX, alignY);
+                frameView->scrollableArea()->scrollIntoView(rect, alignX, alignY, scrollType);
 
                 if (ownerElement && ownerElement->layoutObject()) {
                     if (frameView->safeToPropagateScrollToParent()) {
@@ -550,7 +551,7 @@ void LayoutBox::scrollRectToVisible(const LayoutRect& rect, const ScrollAlignmen
         parentBox = enclosingScrollableBox();
 
     if (parentBox)
-        parentBox->scrollRectToVisible(newRect, alignX, alignY);
+        parentBox->scrollRectToVisible(newRect, alignX, alignY, scrollType);
 }
 
 void LayoutBox::absoluteRects(Vector<IntRect>& rects, const LayoutPoint& accumulatedOffset) const
@@ -773,7 +774,7 @@ void LayoutBox::autoscroll(const IntPoint& positionInRootFrame)
         return;
 
     IntPoint positionInContent = frameView->rootFrameToContents(positionInRootFrame);
-    scrollRectToVisible(LayoutRect(positionInContent, LayoutSize(1, 1)), ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignToEdgeIfNeeded);
+    scrollRectToVisible(LayoutRect(positionInContent, LayoutSize(1, 1)), ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignToEdgeIfNeeded, UserScroll);
 }
 
 // There are two kinds of layoutObject that can autoscroll.