Factor painting code for filters out of FilterEffectRenderer into FilterPainter.

Source/core/paint/FilterPainter.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/FilterPainter.h"
+
+#include "core/paint/LayerPainter.h"
+#include "core/rendering/FilterEffectRenderer.h"
+#include "core/rendering/RenderLayer.h"
+#include "platform/graphics/GraphicsContext.h"
+#include "platform/graphics/filters/FilterEffect.h"
+#include "platform/graphics/filters/SkiaImageFilterBuilder.h"
+
+namespace blink {
+
+FilterPainter::FilterPainter(RenderLayer& renderLayer, GraphicsContext* context, const FloatRect& filterBoxRect, const ClipRect& clipRect, const LayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
+    : m_filterInProgress(false)
+    , m_context(context)
+{
+    SkiaImageFilterBuilder builder(context);
+    RefPtr<FilterEffect> lastEffect = renderLayer.filterRenderer()->lastEffect();
+    lastEffect->determineFilterPrimitiveSubregion(MapRectForward);
+    RefPtr<ImageFilter> imageFilter = builder.build(lastEffect.get(), ColorSpaceDeviceRGB);
+    if (!imageFilter)
+        return;
+
+    if (clipRect.rect() != paintingInfo.paintDirtyRect || clipRect.hasRadius()) {
+        m_clipRecorder = adoptPtr(new ClipRecorder(&renderLayer, context, DisplayItem::ClipLayerFilter, clipRect));
+        if (clipRect.hasRadius())
+            LayerPainter::applyRoundedRectClips(renderLayer, paintingInfo, context, paintFlags, *m_clipRecorder);
+    }
+
+    context->save();
+    FloatRect boundaries = mapImageFilterRect(imageFilter.get(), filterBoxRect);
+    context->translate(filterBoxRect.x(), filterBoxRect.y());
+    boundaries.move(-filterBoxRect.x(), -filterBoxRect.y());
+    context->beginLayer(1, CompositeSourceOver, &boundaries, ColorFilterNone, imageFilter.get());
+    context->translate(-filterBoxRect.x(), -filterBoxRect.y());
+    m_filterInProgress = true;
+}
+
+FilterPainter::~FilterPainter()
+{
+    if (m_filterInProgress) {
+        m_context->endLayer();
+        m_context->restore();
+    }
+}
+
+} // namespace blink