Insert pinch zoom virtual viewport layers to graphics layer tree.

public/web/WebSettings.h

Index: public/web/WebSettings.h
diff --git a/public/web/WebSettings.h b/public/web/WebSettings.h
index 94df385ee14f0ea9c4e272c82cdb959d01e63240..5d9be493ab7fa4f1c88108b374e88868bb36697f 100644
--- a/public/web/WebSettings.h
+++ b/public/web/WebSettings.h
@@ -103,7 +103,6 @@ public:
     virtual void setCSSStickyPositionEnabled(bool) = 0;
     virtual void setExperimentalWebGLEnabled(bool) = 0;
     virtual void setExperimentalWebSocketEnabled(bool) = 0;
-    virtual void setPinchVirtualViewportEnabled(bool) = 0;
     virtual void setFantasyFontFamily(const WebString&, UScriptCode = USCRIPT_COMMON) = 0;
     virtual void setFixedFontFamily(const WebString&, UScriptCode = USCRIPT_COMMON) = 0;
     virtual void setFixedPositionCreatesStackingContext(bool) = 0;
@@ -134,6 +133,8 @@ public:
     virtual void setPasswordEchoEnabled(bool) = 0;
     virtual void setPerTilePaintingEnabled(bool) = 0;
     virtual void setPictographFontFamily(const WebString&, UScriptCode = USCRIPT_COMMON) = 0;
+    virtual void setPinchOverlayScrollbarThickness(int) = 0;
+    virtual void setPinchVirtualViewportEnabled(bool) = 0;
     virtual void setPluginsEnabled(bool) = 0;
     virtual void setPrivilegedWebGLExtensionsEnabled(bool) = 0;
     virtual void setRenderVSyncNotificationEnabled(bool) = 0;