Use float for scroll offset.

third_party/WebKit/Source/core/loader/FrameLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * Copyright (C) 2011 Kris Jordan <krisjordan@gmail.com>
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ skipping 254 matching lines @@
   if (!m_currentItem || !m_frame->view())
     return;
 
   // Shouldn't clobber anything if we might still restore later.
   if (needsHistoryItemRestore(m_loadType) && m_documentLoader &&
       !m_documentLoader->initialScrollState().wasScrolledByUser)
     return;
 
   if (ScrollableArea* layoutScrollableArea =
           m_frame->view()->layoutViewportScrollableArea())
-    m_currentItem->setScrollPoint(layoutScrollableArea->scrollPosition());
-  m_currentItem->setVisualViewportScrollPoint(
-      m_frame->host()->visualViewport().visibleRect().location());
+    m_currentItem->setScrollOffset(layoutScrollableArea->scrollOffset());
+  m_currentItem->setVisualViewportScrollOffset(toScrollOffset(
+      m_frame->host()->visualViewport().visibleRect().location()));
 
   if (m_frame->isMainFrame())
     m_currentItem->setPageScaleFactor(m_frame->page()->pageScaleFactor());
 
   client()->didUpdateCurrentHistoryItem();
 }
 
 void FrameLoader::dispatchUnloadEvent() {
   NavigationDisablerForUnload navigationDisabler;
 
@@ skipping 125 matching lines @@
   if (!oldItem || isBackForwardLoadType(loadType))
     return;
   // Don't propagate state from the old item if this is a different-document navigation, unless the before
   // and after pages are logically related. This means they have the same url (ignoring fragment) and
   // the new item was loaded via reload or client redirect.
   if (navigationType == HistoryNavigationType::DifferentDocument &&
       (historyCommitType != HistoryInertCommit ||
        !equalIgnoringFragmentIdentifier(oldItem->url(), m_currentItem->url())))
     return;
   m_currentItem->setDocumentSequenceNumber(oldItem->documentSequenceNumber());
-  m_currentItem->setScrollPoint(oldItem->scrollPoint());
-  m_currentItem->setVisualViewportScrollPoint(
-      oldItem->visualViewportScrollPoint());
+  m_currentItem->setScrollOffset(oldItem->scrollOffset());
+  m_currentItem->setVisualViewportScrollOffset(
+      oldItem->visualViewportScrollOffset());
   m_currentItem->setPageScaleFactor(oldItem->pageScaleFactor());
   m_currentItem->setScrollRestorationType(oldItem->scrollRestorationType());
 
   // The item sequence number determines whether items are "the same", such back/forward navigation
   // between items with the same item sequence number is a no-op. Only treat this as identical if the
   // navigation did not create a back/forward entry and the url is identical or it was loaded via
   // history.replaceState().
   if (historyCommitType == HistoryInertCommit &&
       (navigationType == HistoryNavigationType::HistoryApi ||
        oldItem->url() == m_currentItem->url())) {
@@ skipping 880 matching lines @@
 
   // This tries to balance:
   //   1. restoring as soon as possible
   //   2. not overriding user scroll (TODO(majidvp): also respect user scale)
   //   3. detecting clamping to avoid repeatedly popping the scroll position
   //      down as the page height increases
   //   4. ignore clamp detection if we are not restoring scroll or after load
   //      completes because that may be because the page will never reach its
   //      previous height
   bool canRestoreWithoutClamping =
-      view->layoutViewportScrollableArea()->clampScrollPosition(
-          m_currentItem->scrollPoint()) == m_currentItem->scrollPoint();
+      view->layoutViewportScrollableArea()->clampScrollOffset(
+          m_currentItem->scrollOffset()) == m_currentItem->scrollOffset();
   bool canRestoreWithoutAnnoyingUser =
       !documentLoader()->initialScrollState().wasScrolledByUser &&
       (canRestoreWithoutClamping || !m_frame->isLoading() ||
        !shouldRestoreScroll);
   if (!canRestoreWithoutAnnoyingUser)
     return;
 
-  if (shouldRestoreScroll)
-    view->layoutViewportScrollableArea()->setScrollPosition(
-        m_currentItem->scrollPoint(), ProgrammaticScroll);
+  if (shouldRestoreScroll) {
+    view->layoutViewportScrollableArea()->setScrollOffset(
+        m_currentItem->scrollOffset(), ProgrammaticScroll);
+  }
 
   // For main frame restore scale and visual viewport position
   if (m_frame->isMainFrame()) {
-    FloatPoint visualViewportOffset(m_currentItem->visualViewportScrollPoint());
+    ScrollOffset visualViewportOffset(
+        m_currentItem->visualViewportScrollOffset());
 
     // If the visual viewport's offset is (-1, -1) it means the history item
     // is an old version of HistoryItem so distribute the scroll between
     // the main frame and the visual viewport as best as we can.
-    if (visualViewportOffset.x() == -1 && visualViewportOffset.y() == -1)
+    if (visualViewportOffset.width() == -1 &&
+        visualViewportOffset.height() == -1) {
       visualViewportOffset =
-          FloatPoint(m_currentItem->scrollPoint() - view->scrollPosition());
+          m_currentItem->scrollOffset() - view->scrollOffset();
+    }
 
     VisualViewport& visualViewport = m_frame->host()->visualViewport();
-    if (shouldRestoreScale && shouldRestoreScroll)
+    if (shouldRestoreScale && shouldRestoreScroll) {
       visualViewport.setScaleAndLocation(m_currentItem->pageScaleFactor(),
-                                         visualViewportOffset);
-    else if (shouldRestoreScale)
+                                         FloatPoint(visualViewportOffset));
+    } else if (shouldRestoreScale) {
       visualViewport.setScale(m_currentItem->pageScaleFactor());
-    else if (shouldRestoreScroll)
-      visualViewport.setLocation(visualViewportOffset);
+    } else if (shouldRestoreScroll) {
+      visualViewport.setLocation(FloatPoint(visualViewportOffset));
+    }
 
     if (ScrollingCoordinator* scrollingCoordinator =
             m_frame->page()->scrollingCoordinator())
       scrollingCoordinator->frameViewRootLayerDidChange(view);
   }
 
   documentLoader()->initialScrollState().didRestoreFromHistory = true;
 }
 
 String FrameLoader::userAgent() const {
@@ skipping 492 matching lines @@
                          m_documentLoader ? m_documentLoader->url() : String());
   return tracedValue;
 }
 
 inline void FrameLoader::takeObjectSnapshot() const {
   TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID("loading", "FrameLoader", this,
                                       toTracedValue());
 }
 
 }  // namespace blink