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 172 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 a fixed value.
+    void setScrollOverride(const DoublePoint& position);
+    // Clear the scroll position override.
+    void clearScrollOverride();
+
     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 437 matching lines @@
         TemporaryChange<bool> m_scope;
     };
 
     // Only for LayoutPart to traverse into sub frames during paint invalidation.
     void invalidateTreeIfNeeded(PaintInvalidationState&);
 
 private:
     explicit FrameView(LocalFrame*);
 
     void setScrollOffset(const DoublePoint&, ScrollType) override;
+    DoublePoint applyScrollOverrideToPosition(const DoublePoint& position);
 
     enum LifeCycleUpdateOption {
         OnlyUpToLayoutClean,
         OnlyUpToCompositingCleanPlusScrolling,
         AllPhasesExceptPaint,
         AllPhases,
     };
 
     void updateLifecyclePhasesInternal(LifeCycleUpdateOption);
     void invalidateTreeIfNeededRecursive();
@@ skipping 203 matching lines @@
 
     bool m_horizontalScrollbarLock;
     bool m_verticalScrollbarLock;
 
     ChildrenWidgetSet m_children;
 
     DoubleSize m_pendingScrollDelta;
     DoublePoint m_scrollPosition;
     IntSize m_contentsSize;
 
+    bool m_scrollOverrideEnabled;
+    DoublePoint m_scrollOverridePosition;
+
     int m_scrollbarsAvoidingResizer;
     bool m_scrollbarsSuppressed;
 
     bool m_inUpdateScrollbars;
 
     OwnPtr<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 55 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