[Pinch-to-zoom] Moved scale factor into PinchViewport

Source/web/WebViewImpl.h

Index: Source/web/WebViewImpl.h
diff --git a/Source/web/WebViewImpl.h b/Source/web/WebViewImpl.h
index 56c93b3f4d9c17331f81258d75391677a6071f4f..c432b39d6354ce661d788d9c500cc3866a26a490 100644
--- a/Source/web/WebViewImpl.h
+++ b/Source/web/WebViewImpl.h
@@ -206,9 +206,14 @@ public:
     virtual void setInitialPageScaleOverride(float) OVERRIDE;
     virtual bool zoomToMultipleTargetsRect(const WebRect&) OVERRIDE;
     virtual float pageScaleFactor() const OVERRIDE;
-    virtual void setPageScaleFactorPreservingScrollOffset(float) OVERRIDE;
+    // TODO(bokan): Remains for legacy pinch. Remove once it's gone.
     virtual void setPageScaleFactor(float scaleFactor, const WebPoint& origin) OVERRIDE;
     virtual void setPageScaleFactorLimits(float minPageScale, float maxPageScale) OVERRIDE;
+    virtual void setMainFrameScrollOffset(const WebPoint&) OVERRIDE;
+    virtual void setPinchViewportScaleFactor(float) OVERRIDE;
+    virtual float pinchViewportScaleFactor() const OVERRIDE;
+    virtual void setPinchViewportOffset(const WebFloatPoint&) OVERRIDE;
+    virtual WebFloatPoint pinchViewportOffset() const OVERRIDE;
     virtual float minimumPageScaleFactor() const OVERRIDE;
     virtual float maximumPageScaleFactor() const OVERRIDE;
     virtual void saveScrollAndScaleState() OVERRIDE;
@@ -519,6 +524,8 @@ public:
     WebLayerTreeView* layerTreeView() const { return m_layerTreeView; }
 
 private:
+    bool pinchVirtualViewportEnabled() const;
+
     float legibleScale() const;
     void refreshPageScaleFactorAfterLayout();
     void resumeTreeViewCommits();