Insert pinch zoom virtual viewport layers to graphics layer tree.

Source/WebKit/chromium/src/WebSettingsImpl.h

Index: Source/WebKit/chromium/src/WebSettingsImpl.h
diff --git a/Source/WebKit/chromium/src/WebSettingsImpl.h b/Source/WebKit/chromium/src/WebSettingsImpl.h
index cd9acde491bec1c2e02ab69a1d19f7b43c8cce6f..f6e08e1236825a8c57ea7e1169ee043e1073a0d2 100644
--- a/Source/WebKit/chromium/src/WebSettingsImpl.h
+++ b/Source/WebKit/chromium/src/WebSettingsImpl.h
@@ -176,6 +176,7 @@ public:
     bool doubleTapToZoomEnabled() const { return m_doubleTapToZoomEnabled; }
     bool perTilePaintingEnabled() const { return m_perTilePaintingEnabled; }
     bool supportDeprecatedTargetDensityDPI() const { return m_supportDeprecatedTargetDensityDPI; }
+    int pinchOverlayScrollbarThickness() const { return m_pinchOverlayScrollbarThickness; }
 
 private:
     WebCore::Settings* m_settings;
@@ -189,6 +190,7 @@ private:
     bool m_doubleTapToZoomEnabled;
     bool m_perTilePaintingEnabled;
     bool m_supportDeprecatedTargetDensityDPI;
+    int m_pinchOverlayScrollbarThickness;
 };
 
 } // namespace WebKit