Adds scroll position/scale emulation to DevTools.

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

Index: third_party/WebKit/Source/core/frame/VisualViewport.h
diff --git a/third_party/WebKit/Source/core/frame/VisualViewport.h b/third_party/WebKit/Source/core/frame/VisualViewport.h
index d15d2345bc75053aadaea36228c1a0fb9e6614e1..d700b8dc485065685d182acc838d542e68b33fc1 100644
--- a/third_party/WebKit/Source/core/frame/VisualViewport.h
+++ b/third_party/WebKit/Source/core/frame/VisualViewport.h
@@ -103,6 +103,11 @@ public:
     void move(const FloatSize&);
     FloatPoint location() const { return m_offset; }
 
+    // Override the visual viewport location and scale with a fixed value.
+    void setScaleAndScrollOverride(float scale, const FloatPoint& location);
+    // Clear the scroll position override.
+    void clearScaleAndScrollOverride();
+
     // Sets the size of the inner viewport when unscaled in CSS pixels.
     void setSize(const IntSize&);
     IntSize size() const { return m_size; }
@@ -239,6 +244,9 @@ private:
     void setupScrollbar(WebScrollbar::Orientation);
     FloatPoint clampOffsetToBoundaries(const FloatPoint&);
 
+    FloatPoint applyScrollOverrideToLocation(const FloatPoint& location);
+    float applyScaleOverrideToScale(float scale);
+
     LocalFrame* mainFrame() const;
 
     FrameHost& frameHost() const
@@ -265,6 +273,10 @@ private:
     float m_topControlsAdjustment;
     float m_maxPageScale;
     bool m_trackPinchZoomStatsForPage;
+
+    bool m_scaleAndScrollOverrideEnabled;
+    float m_scaleAndScrollOverrideScale;
+    FloatPoint m_scaleAndScrollOverrideLocation;
 };
 
 } // namespace blink