Implement a paint offset cache for slimming paint v2

Source/core/paint/VideoPainter.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/VideoPainter.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/FrameView.h"
 #include "core/html/HTMLVideoElement.h"
@@ skipping 21 matching lines @@
     GraphicsContext* context = paintInfo.context;
     LayoutRect contentRect = m_layoutVideo.contentBoxRect();
     contentRect.moveBy(paintOffset);
 
     Optional<FloatClipRecorder> clipRecorder;
     if (!contentRect.contains(rect)) {
         // TODO(chrishtr): this should be pixel-snapped.
         clipRecorder.emplace(*context, m_layoutVideo, paintInfo.phase, FloatRect(contentRect));
     }
 
-    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*context, m_layoutVideo, paintInfo.phase))
+    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*context, m_layoutVideo, paintInfo.phase, paintOffset))
         return;
 
-    LayoutObjectDrawingRecorder drawingRecorder(*context, m_layoutVideo, paintInfo.phase, contentRect);
+    LayoutObjectDrawingRecorder drawingRecorder(*context, m_layoutVideo, paintInfo.phase, contentRect, paintOffset);
 
     if (displayingPoster) {
         ImagePainter(m_layoutVideo).paintIntoRect(context, rect);
     } else if ((paintInfo.globalPaintFlags() & GlobalPaintFlattenCompositingLayers) || !m_layoutVideo.acceleratedRenderingInUse()) {
         SkPaint videoPaint = context->fillPaint();
         videoPaint.setColor(SK_ColorBLACK);
         m_layoutVideo.videoElement()->paintCurrentFrame(context->canvas(), pixelSnappedIntRect(rect), &videoPaint);
     }
 }
 
 } // namespace blink