Adds scroll position/scale emulation to DevTools.

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

Index: third_party/WebKit/Source/core/frame/FrameView.h
diff --git a/third_party/WebKit/Source/core/frame/FrameView.h b/third_party/WebKit/Source/core/frame/FrameView.h
index 36ab2051ea3eb462137e1218767d6dcc38f71d15..c68063bf84ab20a744b8109dfecd2129641174f8 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.h
+++ b/third_party/WebKit/Source/core/frame/FrameView.h
@@ -77,6 +77,7 @@ class LayoutScrollbarPart;
 class LayoutView;
 class PaintInvalidationState;
 class Page;
+class ScrollAndScaleEmulator;
 class ScrollingCoordinator;
 class TracedValue;
 struct AnnotatedRegionValue;
@@ -190,6 +191,9 @@ public:
 
     void setScrollPosition(const DoublePoint&, ScrollType, ScrollBehavior = ScrollBehaviorInstant) override;
 
+    // Override the scroll position with values from the emulator. Passing |nullptr| clears override.
+    void setScrollAndScaleEmulator(const RefPtr<ScrollAndScaleEmulator>&);
+
     void didUpdateElasticOverscroll();
 
     void viewportSizeChanged(bool widthChanged, bool heightChanged);
@@ -877,6 +881,8 @@ private:
     DoublePoint m_scrollPosition;
     IntSize m_contentsSize;
 
+    RefPtr<ScrollAndScaleEmulator> m_scrollAndScaleEmulator;
+
     int m_scrollbarsAvoidingResizer;
     bool m_scrollbarsSuppressed;