Adds scroll position/scale emulation to DevTools.

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

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
@@ skipping 60 matching lines @@
 class Node;
 class LayoutAnalyzer;
 class LayoutBox;
 class LayoutEmbeddedObject;
 class LayoutObject;
 class LayoutReplaced;
 class LayoutScrollbarPart;
 class LayoutView;
 class PaintInvalidationState;
 class Page;
+class ScrollAndScaleEmulator;
 class ScrollingCoordinator;
 class TracedValue;
 struct AnnotatedRegionValue;
 struct CompositedSelection;
 
 typedef unsigned long long DOMTimeStamp;
 
 class CORE_EXPORT FrameView final : public Widget, public PaintInvalidationCapableScrollableArea {
     USING_GARBAGE_COLLECTED_MIXIN(FrameView);
 
@@ skipping 93 matching lines @@
 
     // Scale used to convert incoming input events.
     float inputEventsScaleFactor() const;
 
     // Offset used to convert incoming input events while emulating device metics.
     IntSize inputEventsOffsetForEmulation() const;
     void setInputEventsTransformForEmulation(const IntSize&, float);
 
     void setScrollPosition(const DoublePoint&, ScrollType, ScrollBehavior = ScrollBehaviorInstant) override;
 
+    // Override the scroll position with values from the emulator. Passing |nullptr| clears override.
+    void setScrollAndScaleEmulator(ScrollAndScaleEmulator*);
+
     void didUpdateElasticOverscroll();
 
     void viewportSizeChanged(bool widthChanged, bool heightChanged);
 
     AtomicString mediaType() const;
     void setMediaType(const AtomicString&);
     void adjustMediaTypeForPrinting(bool printing);
 
     WebDisplayMode displayMode() { return m_displayMode; }
     void setDisplayMode(WebDisplayMode);
@@ skipping 551 matching lines @@
     void adjustScrollbarOpacity();
     void adjustScrollPositionFromUpdateScrollbars();
     bool visualViewportSuppliesScrollbars() const;
 
     IntRect rectToCopyOnScroll() const;
 
     bool isFrameViewScrollbar(const Widget* child) const { return horizontalScrollbar() == child || verticalScrollbar() == child; }
 
     ScrollingCoordinator* scrollingCoordinator() const;
 
+    // Calculate the physical minimum/maximum scroll positions without any overrides applied.
+    IntPoint calculateMinimumScrollPosition() const;
+    IntPoint calculateMaximumScrollPosition() const;
+
     void prepareLayoutAnalyzer();
     std::unique_ptr<TracedValue> analyzerCounters();
 
     // LayoutObject for the viewport-defining element (see Document::viewportDefiningElement).
     LayoutObject* viewportLayoutObject() const;
 
     void collectAnnotatedRegions(LayoutObject&, Vector<AnnotatedRegionValue>&) const;
 
     template <typename Function> void forAllNonThrottledFrameViews(const Function&);
 
@@ skipping 97 matching lines @@
 
     bool m_horizontalScrollbarLock;
     bool m_verticalScrollbarLock;
 
     ChildrenWidgetSet m_children;
 
     DoubleSize m_pendingScrollDelta;
     DoublePoint m_scrollPosition;
     IntSize m_contentsSize;
 
+    Member<ScrollAndScaleEmulator> m_scrollAndScaleEmulator;
+
     int m_scrollbarsAvoidingResizer;
     bool m_scrollbarsSuppressed;
 
     bool m_inUpdateScrollbars;
 
     std::unique_ptr<LayoutAnalyzer> m_analyzer;
 
     // Mark if something has changed in the mapping from Frame to GraphicsLayer
     // and the Frame Timing regions should be recalculated.
     bool m_frameTimingRequestsDirty;
@@ skipping 71 matching lines @@
     if (m_visuallyNonEmptyPixelCount > visualPixelThreshold)
         setIsVisuallyNonEmpty();
 }
 
 DEFINE_TYPE_CASTS(FrameView, Widget, widget, widget->isFrameView(), widget.isFrameView());
 DEFINE_TYPE_CASTS(FrameView, ScrollableArea, scrollableArea, scrollableArea->isFrameView(), scrollableArea.isFrameView());
 
 } // namespace blink
 
 #endif // FrameView_h