blink: Add backdrop-filter support

Source/core/paint/DeprecatedPaintLayerPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/DeprecatedPaintLayerPainter.h"
 
 #include "core/frame/Settings.h"
 #include "core/layout/ClipPathOperation.h"
 #include "core/layout/LayoutBlock.h"
@@ skipping 57 matching lines @@
     }
 
     // Non self-painting leaf layers don't need to be painted as their layoutObject() should properly paint itself.
     if (!m_paintLayer.isSelfPaintingLayer() && !m_paintLayer.hasSelfPaintingLayerDescendant())
         return;
 
     if (shouldSuppressPaintingLayer(&m_paintLayer))
         return;
 
     // If this layer is totally invisible then there is nothing to paint.
-    if (!m_paintLayer.layoutObject()->opacity())
+    if (!m_paintLayer.layoutObject()->opacity() && !m_paintLayer.layoutObject()->hasBackdropFilter())
         return;
 
     if (m_paintLayer.paintsWithTransparency(paintingInfo.globalPaintFlags()))
         paintFlags |= PaintLayerHaveTransparency;
 
     LayerFixedPositionRecorder fixedPositionRecorder(*context, *m_paintLayer.layoutObject());
 
     // PaintLayerAppliedTransform is used in LayoutReplica, to avoid applying the transform twice.
     if (m_paintLayer.paintsWithTransform(paintingInfo.globalPaintFlags()) && !(paintFlags & PaintLayerAppliedTransform)) {
         paintLayerWithTransform(context, paintingInfo, paintFlags);
@@ skipping 515 matching lines @@
     if (!m_paintLayer.containsDirtyOverlayScrollbars())
         return;
 
     DeprecatedPaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), paintFlags, LayoutSize(), paintingRoot);
     paintLayer(context, paintingInfo, PaintLayerPaintingOverlayScrollbars);
 
     m_paintLayer.setContainsDirtyOverlayScrollbars(false);
 }
 
 } // namespace blink