Add DidSaveScrollOrScaleState flag to prevent restoreScrollPositionAndViewState restore from default

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 255 matching lines @@
   m_visuallyNonEmptyPixelCount = 0;
   m_isVisuallyNonEmpty = false;
   m_mainThreadScrollingReasons = 0;
   m_layoutObjectCounter.reset();
   clearFragmentAnchor();
   m_viewportConstrainedObjects.reset();
   m_layoutSubtreeRootList.clear();
   m_orthogonalWritingModeRootList.clear();
 }
 
+void FrameView::setScrollFromNavigation() {

[majidvp, 2017/01/24 21:53:52]

nit: please match the declaration order in header file.

+  scrollToFragmentAnchor();

[majidvp, 2017/01/24 21:53:52]

In this case, 
scrollToFragment does not honor history.scrollRestoration

Can it cause an issue?

[chaopeng, 2017/01/25 15:22:38]

No, in this case m_fragmentAnchor is null and scrollToFragment will do nothing
because we dont set m_fragmentAnchor in this case. 
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/frame/Fra...

[majidvp, 2017/01/25 20:31:59]

Are you sure? If the fragmentAnchor is always nil in such cases then why do we
even bother to call scrollToFragmentAnchor?

+  frame().loader().restoreScrollPositionAndViewState();
+}
+
 // Call function for each non-throttled frame view in pre tree order.
 // Note it needs a null check of the frame's layoutView to access it in case of
 // detached frames.
 template <typename Function>
 void FrameView::forAllNonThrottledFrameViews(const Function& function) {
   if (shouldThrottleRendering())
     return;
 
   function(*this);
 
@@ skipping 254 matching lines @@
 
   updateParentScrollableAreaSet();
 
   if (frameSizeChanged) {
     viewportSizeChanged(newRect.width() != oldRect.width(),
                         newRect.height() != oldRect.height());
 
     if (m_frame->isMainFrame())
       m_frame->host()->visualViewport().mainFrameDidChangeSize();
 
-    frame().loader().restoreScrollPositionAndViewState();
+    setScrollFromNavigation();
   }
 }
 
 Page* FrameView::page() const {
   return frame().page();
 }
 
 LayoutView* FrameView::layoutView() const {
   return frame().contentLayoutObject();
 }
@@ skipping 100 matching lines @@
   ScrollableArea::contentsResized();
 
   Page* page = frame().page();
   if (!page)
     return;
 
   updateParentScrollableAreaSet();
 
   page->chromeClient().contentsSizeChanged(m_frame.get(), size);
 
-  // Ensure the scrollToFragmentAnchor is called before
-  // restoreScrollPositionAndViewState when reload
-  scrollToFragmentAnchor();
-  frame().loader().restoreScrollPositionAndViewState();
+  setScrollFromNavigation();
 }
 
 void FrameView::adjustViewSize() {
   if (m_suppressAdjustViewSize)
     return;
 
   LayoutViewItem layoutViewItem = this->layoutViewItem();
   if (layoutViewItem.isNull())
     return;
 
@@ skipping 4312 matching lines @@
   // This is the top-level frame, so no mapping necessary.
   if (m_frame->isMainFrame())
     return;
 
   LayoutRect viewportIntersectionRect(remoteViewportIntersection());
   transformState.move(
       LayoutSize(-viewportIntersectionRect.x(), -viewportIntersectionRect.y()));
 }
 
 }  // namespace blink