Turn FrameView's paintBehavior into a real global

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 3b9352dfb0b5cd7588dce6db828fd7b68ee4e8f8..8818d09e0dec36c8c3462143717431868d9e54bf 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -1929,13 +1929,11 @@ void WebViewImpl::paintCompositedDeprecated(WebCanvas* canvas, const WebRect& re
     //       the compositor.
     ASSERT(isAcceleratedCompositingActive());
 
-    FrameView* view = page()->deprecatedLocalMainFrame()->view();
-    PaintBehavior oldPaintBehavior = view->paintBehavior();
-    view->setPaintBehavior(oldPaintBehavior | PaintBehaviorFlattenCompositingLayers);
+    gGlobalPaintFlags = GlobalPaintFlattenCompositingLayers;
 
     PageWidgetDelegate::paint(*m_page, pageOverlays(), canvas, rect, *m_page->deprecatedLocalMainFrame());
 
-    view->setPaintBehavior(oldPaintBehavior);
+    gGlobalPaintFlags = GlobalPaintNormalPhase;
 }
 #endif