Added pinch viewport offset to history item.

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 31 matching lines @@
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/editing/Editor.h"
 #include "core/editing/UndoStack.h"
 #include "core/events/Event.h"
 #include "core/events/PageTransitionEvent.h"
 #include "core/fetch/FetchContext.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/fetch/ResourceLoader.h"
 #include "core/frame/DOMWindow.h"
+#include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/PinchViewport.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/html/HTMLFormElement.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/inspector/InspectorController.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/loader/DocumentLoadTiming.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/loader/FormState.h"
 #include "core/loader/FormSubmission.h"
@@ skipping 112 matching lines @@
 void FrameLoader::saveScrollState()
 {
     if (!m_currentItem || !m_frame->view())
         return;
 
     // Shouldn't clobber anything if we might still restore later.
     if (needsHistoryItemRestore(m_loadType) && !m_frame->view()->wasScrolledByUser())
         return;
 
     m_currentItem->setScrollPoint(m_frame->view()->scrollPosition());
+
+    if (m_frame->document()->settings()->pinchVirtualViewportEnabled())
+        m_currentItem->setPinchViewportScrollPoint(m_frame->host()->pinchViewport().visibleRect().location());
+    else
+        m_currentItem->setPinchViewportScrollPoint(FloatPoint(-1, -1));
+
     if (m_frame->isMainFrame() && !m_frame->page()->inspectorController().deviceEmulationEnabled())
         m_currentItem->setPageScaleFactor(m_frame->page()->pageScaleFactor());
 
     m_client->didUpdateCurrentHistoryItem();
 }
 
 void FrameLoader::clearScrollPositionAndViewState()
 {
     ASSERT(m_frame->isMainFrame());
     if (!m_currentItem)
@@ skipping 783 matching lines @@
         return;
 
     if (!needsHistoryItemRestore(m_loadType))
         return;
 
     // This tries to balance 1. restoring as soon as possible, 2. detecting
     // clamping to avoid repeatedly popping the scroll position down as the
     // page height increases, 3. ignore clamp detection after load completes
     // because that may be because the page will never reach its previous
     // height.
-    bool canRestoreWithoutClamping = view->clampOffsetAtScale(m_currentItem->scrollPoint(), m_currentItem->pageScaleFactor()) == m_currentItem->scrollPoint();
+    float mainFrameScale = m_frame->document()->settings()->pinchVirtualViewportEnabled() ? 1 : m_currentItem->pageScaleFactor();
+    bool canRestoreWithoutClamping = view->clampOffsetAtScale(m_currentItem->scrollPoint(), mainFrameScale) == m_currentItem->scrollPoint();
     bool canRestoreWithoutAnnoyingUser = !view->wasScrolledByUser() && (canRestoreWithoutClamping || m_state == FrameStateComplete);
     if (!canRestoreWithoutAnnoyingUser)
         return;
 
-    if (m_frame->isMainFrame() && m_currentItem->pageScaleFactor())
-        m_frame->page()->setPageScaleFactor(m_currentItem->pageScaleFactor(), m_currentItem->scrollPoint());
-    else
+    if (m_frame->isMainFrame() && m_currentItem->pageScaleFactor()) {
+        FloatPoint pinchViewportOffset(m_currentItem->pinchViewportScrollPoint());
+        IntPoint frameScrollOffset(m_currentItem->scrollPoint());
+
+        m_frame->page()->setPageScaleFactor(m_currentItem->pageScaleFactor(), frameScrollOffset);

[aelias_OOO_until_Jul13, 2014/05/07 08:06:03]

In the legacy historyitem case, I think you also need to subtract the computed
pinchViewportOffset from the scrollPoint.  Your unit test fails to catch this
bug because the outer viewport is at the bottom right of the document in that
test case.

[aelias_OOO_until_Jul13, 2014/05/07 08:41:35]

Ignore that comment, since I realized it has to always be zero in the
non-bottom-right case anyway.  lgtm as is.

+
+        if (m_frame->document()->settings()->pinchVirtualViewportEnabled()) {
+            // If the pinch 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 pinch viewport as best as we can.
+            if (pinchViewportOffset.x() == -1 && pinchViewportOffset.y() == -1)
+                pinchViewportOffset = IntPoint(frameScrollOffset - view->scrollPosition());
+
+            m_frame->host()->pinchViewport().setLocation(pinchViewportOffset);
+        }
+    } else {
         view->setScrollPositionNonProgrammatically(m_currentItem->scrollPoint());
+    }
 
     if (m_frame->isMainFrame()) {
         if (ScrollingCoordinator* scrollingCoordinator = m_frame->page()->scrollingCoordinator())
             scrollingCoordinator->frameViewRootLayerDidChange(view);
     }
 }
 
 void FrameLoader::detachChildren()
 {
     typedef Vector<RefPtr<LocalFrame> > FrameVector;
@@ skipping 390 matching lines @@
 {
     SandboxFlags flags = m_forcedSandboxFlags;
     if (LocalFrame* parentFrame = m_frame->tree().parent())
         flags |= parentFrame->document()->sandboxFlags();
     if (HTMLFrameOwnerElement* ownerElement = m_frame->ownerElement())
         flags |= ownerElement->sandboxFlags();
     return flags;
 }
 
 } // namespace WebCore