Attempt scroll restoration anytime viewport size changes

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 388 matching lines @@
 
     updateScrollableAreaSet();
 
     if (LayoutView* layoutView = this->layoutView()) {
         if (layoutView->usesCompositing())
             layoutView->compositor()->frameViewDidChangeSize();
     }
 
     viewportSizeChanged(newRect.width() != oldRect.width(), newRect.height() != oldRect.height());
 
-    if (oldRect.size() != newRect.size() && m_frame->isMainFrame())
-        page()->frameHost().visualViewport().mainFrameDidChangeSize();
+    if (oldRect.size() != newRect.size()) {
+        if (m_frame->isMainFrame())
+            m_frame->host()->visualViewport().mainFrameDidChangeSize();
+        frame().loader().restoreScrollPositionAndViewState();
+    }
 }
 
 Page* FrameView::page() const
 {
     return frame().page();
 }
 
 LayoutView* FrameView::layoutView() const
 {
     return frame().contentLayoutObject();
@@ skipping 81 matching lines @@
     updateScrollbars(scrollOffsetDouble());
     ScrollableArea::contentsResized();
 
     Page* page = frame().page();
     if (!page)
         return;
 
     updateScrollableAreaSet();
 
     page->chromeClient().contentsSizeChanged(m_frame.get(), size);
-}
-
-IntPoint FrameView::clampOffsetAtScale(const IntPoint& offset, float scale) const
-{
-    IntPoint maxScrollExtent(contentsSize().width() - scrollOrigin().x(), contentsSize().height() - scrollOrigin().y());
-    FloatSize scaledSize = visibleContentSize();
-    if (scale)
-        scaledSize.scale(1 / scale);
-
-    IntPoint clampedOffset = offset;
-    clampedOffset = clampedOffset.shrunkTo(maxScrollExtent - expandedIntSize(scaledSize));
-    clampedOffset = clampedOffset.expandedTo(-scrollOrigin());
-
-    return clampedOffset;
+    frame().loader().restoreScrollPositionAndViewState();
 }
 
 void FrameView::adjustViewSize()
 {
     LayoutView* layoutView = this->layoutView();
     if (!layoutView)
         return;
 
     ASSERT(m_frame->view() == this);
 
@@ skipping 247 matching lines @@
         document->styleResolverChanged();
         document->mediaQueryAffectingValueChanged();
     } else if (wasResized) {
         document->evaluateMediaQueryList();
     }
 
     document->updateLayoutTreeIfNeeded();
     lifecycle().advanceTo(DocumentLifecycle::StyleClean);
 
     if (m_frame->isMainFrame() && !m_viewportScrollableArea) {
-        ScrollableArea& visualViewport = page()->frameHost().visualViewport();
+        ScrollableArea& visualViewport = m_frame->host()->visualViewport();
         ScrollableArea* layoutViewport = layoutViewportScrollableArea();
         bool invertScrollOrder = m_frame->settings()->invertViewportScrollOrder();
         ASSERT(layoutViewport);
         m_viewportScrollableArea = RootFrameViewport::create(visualViewport, *layoutViewport, invertScrollOrder);
     }
 }
 
 static inline void layoutFromRootObject(LayoutObject& root)
 {
     LayoutState layoutState(root);
@@ skipping 1384 matching lines @@
     m_inputEventsScaleFactorForEmulation = contentScaleFactor;
 }
 
 IntSize FrameView::inputEventsOffsetForEmulation() const
 {
     return m_inputEventsOffsetForEmulation;
 }
 
 float FrameView::inputEventsScaleFactor() const
 {
-    float pageScale = m_frame->page()->frameHost().visualViewport().scale();
+    float pageScale = m_frame->host()->visualViewport().scale();
     return pageScale * m_inputEventsScaleFactorForEmulation;
 }
 
 bool FrameView::scrollbarsCanBeActive() const
 {
     if (m_frame->view() != this)
         return false;
 
     return !!m_frame->document();
 }
@@ skipping 1336 matching lines @@
 }
 
 FloatPoint FrameView::rootFrameToContents(const FloatPoint& windowPoint) const
 {
     FloatPoint framePoint = convertFromContainingWindow(windowPoint);
     return frameToContents(framePoint);
 }
 
 IntRect FrameView::viewportToContents(const IntRect& rectInViewport) const
 {
-    IntRect rectInRootFrame = page()->frameHost().visualViewport().viewportToRootFrame(rectInViewport);
+    IntRect rectInRootFrame = m_frame->host()->visualViewport().viewportToRootFrame(rectInViewport);
     IntRect frameRect = convertFromContainingWindow(rectInRootFrame);
     return frameToContents(frameRect);
 }
 
 IntPoint FrameView::viewportToContents(const IntPoint& pointInViewport) const
 {
-    IntPoint pointInRootFrame = page()->frameHost().visualViewport().viewportToRootFrame(pointInViewport);
+    IntPoint pointInRootFrame = m_frame->host()->visualViewport().viewportToRootFrame(pointInViewport);
     IntPoint pointInFrame = convertFromContainingWindow(pointInRootFrame);
     return frameToContents(pointInFrame);
 }
 
 IntRect FrameView::contentsToViewport(const IntRect& rectInContents) const
 {
     IntRect rectInFrame = contentsToFrame(rectInContents);
     IntRect rectInRootFrame = convertToContainingWindow(rectInFrame);
-    return page()->frameHost().visualViewport().rootFrameToViewport(rectInRootFrame);
+    return m_frame->host()->visualViewport().rootFrameToViewport(rectInRootFrame);
 }
 
 IntPoint FrameView::contentsToViewport(const IntPoint& pointInContents) const
 {
     IntPoint pointInFrame = contentsToFrame(pointInContents);
     IntPoint pointInRootFrame = convertToContainingWindow(pointInFrame);
-    return page()->frameHost().visualViewport().rootFrameToViewport(pointInRootFrame);
+    return m_frame->host()->visualViewport().rootFrameToViewport(pointInRootFrame);
 }
 
 IntRect FrameView::contentsToScreen(const IntRect& rect) const
 {
     HostWindow* window = hostWindow();
     if (!window)
         return IntRect();
     return window->viewportToScreen(contentsToViewport(rect));
 }
 
 IntRect FrameView::soonToBeRemovedContentsToUnscaledViewport(const IntRect& rectInContents) const
 {
     IntRect rectInFrame = contentsToFrame(rectInContents);
     IntRect rectInRootFrame = convertToContainingWindow(rectInFrame);
-    return enclosingIntRect(page()->frameHost().visualViewport().mainViewToViewportCSSPixels(rectInRootFrame));
+    return enclosingIntRect(m_frame->host()->visualViewport().mainViewToViewportCSSPixels(rectInRootFrame));
 }
 
 IntPoint FrameView::soonToBeRemovedUnscaledViewportToContents(const IntPoint& pointInViewport) const
 {
-    IntPoint pointInRootFrame = flooredIntPoint(page()->frameHost().visualViewport().viewportCSSPixelsToRootFrame(pointInViewport));
+    IntPoint pointInRootFrame = flooredIntPoint(m_frame->host()->visualViewport().viewportCSSPixelsToRootFrame(pointInViewport));
     IntPoint pointInThisFrame = convertFromContainingWindow(pointInRootFrame);
     return frameToContents(pointInThisFrame);
 }
 
 bool FrameView::containsScrollbarsAvoidingResizer() const
 {
     return !m_scrollbarsAvoidingResizer;
 }
 
 void FrameView::adjustScrollbarsAvoidingResizerCount(int overlapDelta)
@@ skipping 369 matching lines @@
 
     if (!graphicsLayer)
         return;
 
     DeprecatedPaintLayer::mapRectToPaintInvalidationBacking(localFrame->contentLayoutObject(), paintInvalidationContainer, viewRect);
 
     graphicsLayerTimingRequests.add(graphicsLayer, Vector<std::pair<int64_t, WebRect>>()).storedValue->value.append(std::make_pair(m_frame->frameID(), enclosingIntRect(viewRect)));
 }
 
 } // namespace blink