[SPv2] Paint accelerated canvases as foreign layers.

third_party/WebKit/Source/core/paint/HTMLCanvasPainter.cpp

Index: third_party/WebKit/Source/core/paint/HTMLCanvasPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/HTMLCanvasPainter.cpp b/third_party/WebKit/Source/core/paint/HTMLCanvasPainter.cpp
index a1136ebb46d64e5e8271b9707761a5f205f9caab..4ec8ab0f32b3c32194deed8d12a9606ce5daa3f1 100644
--- a/third_party/WebKit/Source/core/paint/HTMLCanvasPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/HTMLCanvasPainter.cpp
@@ -5,25 +5,41 @@
 #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.
@@ -45,7 +61,7 @@ void HTMLCanvasPainter::paintReplaced(const PaintInfo& paintInfo, const LayoutPo
 
     InterpolationQuality previousInterpolationQuality = context.imageInterpolationQuality();
     context.setImageInterpolationQuality(interpolationQuality);
-    toHTMLCanvasElement(m_layoutHTMLCanvas.node())->paint(context, paintRect);
+    canvas->paint(context, paintRect);
     context.setImageInterpolationQuality(previousInterpolationQuality);
 
     if (clip)