Enable fast/images with slimming paint

Source/core/paint/HTMLCanvasClipper.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/HTMLCanvasClipper.h"
+
+#include "core/paint/ClipRecorder.h"
+#include "core/paint/ViewDisplayList.h"
+#include "core/rendering/PaintInfo.h"
+#include "core/rendering/RenderHTMLCanvas.h"
+#include "core/rendering/RenderView.h"
+#include "platform/RuntimeEnabledFeatures.h"
+
+namespace blink {
+
+HTMLCanvasClipper::HTMLCanvasClipper(RenderHTMLCanvas& canvas, const PaintInfo& paintInfo, const LayoutRect& clipRect)

[chrishtr, 2014/11/25 00:29:58]

Can this be easily unified with BoxClipper now that my BoxClipper refactor is
landed?

+    : m_clipRect(clipRect)
+    , m_paintInfo(paintInfo)
+    , m_canvas(canvas)
+{
+    DisplayItem::Type type = DisplayItem::paintPhaseToClipType(paintInfo.phase);
+    OwnPtr<ClipDisplayItem> clipDisplayItem = adoptPtr(new ClipDisplayItem(&m_canvas, type, pixelSnappedIntRect(clipRect)));
+
+    if (RuntimeEnabledFeatures::slimmingPaintEnabled())
+        m_canvas.view()->viewDisplayList().add(clipDisplayItem.release());
+    else
+        clipDisplayItem->replay(paintInfo.context);
+}
+
+HTMLCanvasClipper::~HTMLCanvasClipper()
+{
+    OwnPtr<EndClipDisplayItem> endClipDisplayItem = adoptPtr(new EndClipDisplayItem(&m_canvas));
+
+    if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
+        m_canvas.view()->viewDisplayList().add(endClipDisplayItem.release());
+    } else {
+        endClipDisplayItem->replay(m_paintInfo.context);
+    }
+}
+
+} // namespace blink