Use correct ScrollbarTheme to paintScrollCorner

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/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
@@ skipping 178 matching lines @@
     // to be part of the next frame.
     memoryCache()->updateFramePaintTimestamp();
     s_inPaintContents = false;
   }
 
   probe::didPaint(layoutView->frame(), 0, context, LayoutRect(rect));
 }
 
 void FramePainter::paintScrollbars(GraphicsContext& context,
                                    const IntRect& rect) {
+  ScrollbarTheme* scrollbarTheme = nullptr;
   if (frameView().horizontalScrollbar() &&
-      !frameView().layerForHorizontalScrollbar())
+      !frameView().layerForHorizontalScrollbar()) {
     paintScrollbar(context, *frameView().horizontalScrollbar(), rect);
+    scrollbarTheme = &frameView().horizontalScrollbar()->theme();
+  }
   if (frameView().verticalScrollbar() &&
-      !frameView().layerForVerticalScrollbar())
+      !frameView().layerForVerticalScrollbar()) {
     paintScrollbar(context, *frameView().verticalScrollbar(), rect);
+    scrollbarTheme = &frameView().horizontalScrollbar()->theme();
+  }
 
   if (frameView().layerForScrollCorner())
     return;
 
-  paintScrollCorner(context, frameView().scrollCornerRect());
+  DCHECK(scrollbarTheme);
+  scrollbarTheme = scrollbarTheme ? scrollbarTheme : &ScrollbarTheme::theme();
+  paintScrollCorner(context, *scrollbarTheme, frameView().scrollCornerRect());
 }
 
 void FramePainter::paintScrollCorner(GraphicsContext& context,
+                                     ScrollbarTheme& theme,

[bokan, 2017/03/13 13:52:09]

Rather than passing the theme in, just computed it inside here, rather than
above and in PLC.

                                      const IntRect& cornerRect) {
   if (frameView().scrollCorner()) {
     bool needsBackground = frameView().frame().isMainFrame();
     if (needsBackground &&
         !LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(
             context, *frameView().layoutView(),
             DisplayItem::kScrollbarCorner)) {
       LayoutObjectDrawingRecorder drawingRecorder(
           context, *frameView().layoutView(), DisplayItem::kScrollbarCorner,
           FloatRect(cornerRect));
       context.fillRect(cornerRect, frameView().baseBackgroundColor());
     }
     ScrollbarPainter::paintIntoRect(*frameView().scrollCorner(), context,
                                     cornerRect.location(),
                                     LayoutRect(cornerRect));
     return;
   }
 
-  ScrollbarTheme::theme().paintScrollCorner(context, *frameView().layoutView(),
-                                            cornerRect);
+  theme.paintScrollCorner(context, *frameView().layoutView(), cornerRect);
 }
 
 void FramePainter::paintScrollbar(GraphicsContext& context,
                                   Scrollbar& bar,
                                   const IntRect& rect) {
   bool needsBackground =
       bar.isCustomScrollbar() && frameView().frame().isMainFrame();
   if (needsBackground) {
     IntRect toFill = bar.frameRect();
     toFill.intersect(rect);
     context.fillRect(toFill, frameView().baseBackgroundColor());
   }
 
   bar.paint(context, CullRect(rect));
 }
 
 const FrameView& FramePainter::frameView() {
   DCHECK(m_frameView);
   return *m_frameView;
 }
 
 }  // namespace blink