Refactor DrawingRecorders to check for cached drawings earlier

Source/core/paint/BlockFlowPainter.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/BlockFlowPainter.h"
 
 #include "core/layout/FloatingObjects.h"
 #include "core/layout/LayoutBlockFlow.h"
 #include "core/paint/ClipScope.h"
@@ skipping 44 matching lines @@
 
     LayoutUnit lastTop = 0;
     LayoutUnit lastLeft = m_layoutBlockFlow.logicalLeftSelectionOffset(&m_layoutBlockFlow, lastTop);
     LayoutUnit lastRight = m_layoutBlockFlow.logicalRightSelectionOffset(&m_layoutBlockFlow, lastTop);
 
     LayoutRect bounds;
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         bounds = m_layoutBlockFlow.visualOverflowRect();
         bounds.moveBy(paintOffset);
     }
-    LayoutObjectDrawingRecorder recorder(*paintInfo.context, m_layoutBlockFlow, DisplayItem::SelectionGap, bounds);
-    ClipScope clipScope(paintInfo.context);
+
+    // Only create a DrawingRecorder and ClipScope if skipRecording is false. This logic is needed
+    // because selectionGaps(...) needs to be called even when we do not record.
+    bool skipRecording = LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*paintInfo.context, m_layoutBlockFlow, DisplayItem::SelectionGap);
+    Optional<DrawingRecorder> drawingRecorder;
+    Optional<ClipScope> clipScope;
+    if (!skipRecording) {
+        drawingRecorder.emplace(*paintInfo.context, m_layoutBlockFlow, DisplayItem::SelectionGap, bounds);
+        clipScope.emplace(paintInfo.context);
+    }
 
     LayoutRect gapRectsBounds = m_layoutBlockFlow.selectionGaps(&m_layoutBlockFlow, paintOffset, LayoutSize(), lastTop, lastLeft, lastRight,
-        recorder.canUseCachedDrawing() ? nullptr : &paintInfo,
-        recorder.canUseCachedDrawing() ? nullptr : &clipScope);
+        skipRecording ? nullptr : &paintInfo,
+        skipRecording ? nullptr : &(*clipScope));
     // TODO(wkorman): Rework below to process paint invalidation rects during layout rather than paint.
     if (!gapRectsBounds.isEmpty()) {
         DeprecatedPaintLayer* layer = m_layoutBlockFlow.enclosingLayer();
         gapRectsBounds.moveBy(-paintOffset);
         if (!m_layoutBlockFlow.hasLayer()) {
             LayoutRect localBounds(gapRectsBounds);
             m_layoutBlockFlow.flipForWritingMode(localBounds);
             gapRectsBounds = LayoutRect(m_layoutBlockFlow.localToContainerQuad(FloatRect(localBounds), layer->layoutObject()).enclosingBoundingBox());
             if (layer->layoutObject()->hasOverflowClip())
                 gapRectsBounds.move(layer->layoutBox()->scrolledContentOffset());
         }
         layer->addBlockSelectionGapsBounds(gapRectsBounds);
     }
 }
 
 } // namespace blink