Skip paint chunks with effectively invisible opacity.

third_party/WebKit/Source/core/paint/PaintLayerPainter.h

 // 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.
 
 #ifndef PaintLayerPainter_h
 #define PaintLayerPainter_h
 
 #include "core/CoreExport.h"
 #include "core/paint/PaintLayerFragment.h"
 #include "core/paint/PaintLayerPaintingInfo.h"
@@ skipping 36 matching lines @@
   PaintResult PaintLayerContents(GraphicsContext&,
                                  const PaintLayerPaintingInfo&,
                                  PaintLayerFlags,
                                  FragmentPolicy = kAllowMultipleFragments);
 
   void PaintOverlayScrollbars(GraphicsContext&,
                               const LayoutRect& damage_rect,
                               const GlobalPaintFlags);
 
  private:
-  friend class PaintLayerPainterTest;
-
   enum ClipState { kHasNotClipped, kHasClipped };
 
   inline bool IsFixedPositionObjectInPagedMedia();
 
   // "For paged media, boxes with fixed positions are repeated on every page."
   // https://www.w3.org/TR/2011/REC-CSS2-20110607/visuren.html#fixed-positioning
   // Repeats singleFragmentIgnoredPagination of the fixed-position object in
   // each page, with paginationOffset and layerBounds adjusted for each page.
   // TODO(wangxianzhu): Fold this into PaintLayer::collectFragments().
   void RepeatFixedPositionObjectInPages(
@@ skipping 70 matching lines @@
   void FillMaskingFragment(GraphicsContext&, const ClipRect&);
 
   static bool NeedsToClip(const PaintLayerPaintingInfo& local_painting_info,
                           const ClipRect&);
 
   // Returns whether this layer should be painted during sofware painting (i.e.,
   // not via calls from CompositedLayerMapping to draw into composited layers).
   bool ShouldPaintLayerInSoftwareMode(const GlobalPaintFlags,
                                       PaintLayerFlags paint_flags);
 
-  // Returns true if the painted output of this PaintLayer and its children is
-  // invisible and therefore can't impact painted output.
-  bool PaintedOutputInvisible(const PaintLayerPaintingInfo&);
-
   PaintLayer& paint_layer_;
 };
 
 }  // namespace blink
 
 #endif  // PaintLayerPainter_h