Don't paint empty scroll corner

third_party/WebKit/Source/core/paint/FramePainter.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 "core/paint/FramePainter.h"
 
 #include "core/editing/markers/DocumentMarkerController.h"
 #include "core/frame/FrameView.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/layout/LayoutView.h"
@@ skipping 188 matching lines @@
 
 void FramePainter::PaintScrollbars(GraphicsContext& context,
                                    const IntRect& rect) {
   if (GetFrameView().HorizontalScrollbar() &&
       !GetFrameView().LayerForHorizontalScrollbar())
     PaintScrollbar(context, *GetFrameView().HorizontalScrollbar(), rect);
   if (GetFrameView().VerticalScrollbar() &&
       !GetFrameView().LayerForVerticalScrollbar())
     PaintScrollbar(context, *GetFrameView().VerticalScrollbar(), rect);
 
-  if (GetFrameView().LayerForScrollCorner())
+  if (GetFrameView().LayerForScrollCorner() ||
+      !GetFrameView().IsScrollCornerVisible()) {
     return;
+  }
 
   PaintScrollCorner(context, GetFrameView().ScrollCornerRect());
 }
 
 void FramePainter::PaintScrollCorner(GraphicsContext& context,
                                      const IntRect& corner_rect) {
   if (GetFrameView().ScrollCorner()) {
     bool needs_background = GetFrameView().GetFrame().IsMainFrame();
     if (needs_background &&
         !LayoutObjectDrawingRecorder::UseCachedDrawingIfPossible(
@@ skipping 37 matching lines @@
 
   bar.Paint(context, CullRect(rect));
 }
 
 const FrameView& FramePainter::GetFrameView() {
   DCHECK(frame_view_);
   return *frame_view_;
 }
 
 }  // namespace blink