[SPv2] Paint accelerated canvases as foreign layers.

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"
 #include "core/paint/PaintInfo.h"
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/graphics/paint/ClipRecorder.h"
+#include "platform/graphics/paint/ForeignLayerDisplayItem.h"
 
 namespace blink {
 
 void HTMLCanvasPainter::paintReplaced(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     GraphicsContext& context = paintInfo.context;
-    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, m_layoutHTMLCanvas, paintInfo.phase))
-        return;
 
     LayoutRect contentRect = m_layoutHTMLCanvas.contentBoxRect();
     contentRect.moveBy(paintOffset);
     LayoutRect paintRect = m_layoutHTMLCanvas.replacedContentRect();
     paintRect.moveBy(paintOffset);
 
+    HTMLCanvasElement* canvas = toHTMLCanvasElement(m_layoutHTMLCanvas.node());
+
+    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()
+        && canvas->renderingContext() && canvas->renderingContext()->isAccelerated()) {
+        if (WebLayer* layer = canvas->renderingContext()->platformLayer()) {
+            IntRect pixelSnappedRect = pixelSnappedIntRect(contentRect);
+            recordForeignLayer(
+                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);
-    toHTMLCanvasElement(m_layoutHTMLCanvas.node())->paint(context, paintRect);
+    canvas->paint(context, paintRect);
     context.setImageInterpolationQuality(previousInterpolationQuality);
 
     if (clip)
         context.restore();
 }
 
 } // namespace blink