Always fallback to checking bitmaps during under-invalidation checking

third_party/WebKit/Source/core/paint/HTMLCanvasPainter.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/HTMLCanvasPainter.h"
 
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/layout/LayoutHTMLCanvas.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
@@ skipping 23 matching lines @@
                 context, m_layoutHTMLCanvas, DisplayItem::ForeignLayerCanvas,
                 layer, pixelSnappedRect.location(), pixelSnappedRect.size());
             return;
         }
     }
 
     if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, m_layoutHTMLCanvas, paintInfo.phase))
         return;
 
     LayoutObjectDrawingRecorder drawingRecorder(context, m_layoutHTMLCanvas, paintInfo.phase, contentRect);
-#if ENABLE(ASSERT)
-    // The drawing may be in display list mode or image mode, producing different pictures for the same result.
-    drawingRecorder.setUnderInvalidationCheckingMode(DrawingDisplayItem::CheckBitmap);
-#endif
 
     bool clip = !contentRect.contains(paintRect);
     if (clip) {
         context.save();
         // TODO(chrishtr): this should be pixel-snapped.
         context.clip(FloatRect(contentRect));
     }
 
     // FIXME: InterpolationNone should be used if ImageRenderingOptimizeContrast is set.
     // See bug for more details: crbug.com/353716.
     InterpolationQuality interpolationQuality = m_layoutHTMLCanvas.style()->imageRendering() == ImageRenderingOptimizeContrast ? InterpolationLow : CanvasDefaultInterpolationQuality;
     if (m_layoutHTMLCanvas.style()->imageRendering() == ImageRenderingPixelated)
         interpolationQuality = InterpolationNone;
 
     InterpolationQuality previousInterpolationQuality = context.imageInterpolationQuality();
     context.setImageInterpolationQuality(interpolationQuality);
     canvas->paint(context, paintRect);
     context.setImageInterpolationQuality(previousInterpolationQuality);
 
     if (clip)
         context.restore();
 }
 
 } // namespace blink