Implement clip and scroll DisplayItems for PartPainter

Source/core/paint/RoundedInnerRectClipper.cpp

Index: Source/core/paint/RoundedInnerRectClipper.cpp
diff --git a/Source/core/paint/RoundedInnerRectClipper.cpp b/Source/core/paint/RoundedInnerRectClipper.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..a3825bbcf0dac6d936682cd8bb5076845ed77773
--- /dev/null
+++ b/Source/core/paint/RoundedInnerRectClipper.cpp
@@ -0,0 +1,72 @@
+// Copyright 2015 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/RoundedInnerRectClipper.h"
+
+#include "core/rendering/PaintInfo.h"
+#include "core/rendering/RenderBox.h"
+#include "platform/graphics/paint/ClipDisplayItem.h"
+#include "platform/graphics/paint/DisplayItemList.h"
+
+namespace blink {
+
+RoundedInnerRectClipper::RoundedInnerRectClipper(RenderObject& renderer, const PaintInfo& paintInfo, const LayoutRect& rect, const FloatRoundedRect& clipRect, RoundedInnerRectClipperBehavior behavior)
+    : m_renderer(renderer)
+    , m_paintInfo(paintInfo)
+    , m_useDisplayItemList(RuntimeEnabledFeatures::slimmingPaintEnabled() && behavior == ApplyToDisplayListIfEnabled)
+{
+    DisplayItem::Type clipType = m_useDisplayItemList ? m_paintInfo.displayItemTypeForClipping() : DisplayItem::ClipBoxForeground;
+    OwnPtr<ClipDisplayItem> clipDisplayItem = ClipDisplayItem::create(renderer.displayItemClient(), clipType, LayoutRect::infiniteIntRect());
+
+    if (clipRect.isRenderable()) {
+        clipDisplayItem->roundedRectClips().append(clipRect);
+    } else {
+        // We create a rounded rect for each of the corners and clip it, while making sure we clip opposing corners together.
+        if (!clipRect.radii().topLeft().isEmpty() || !clipRect.radii().bottomRight().isEmpty()) {
+            FloatRect topCorner(clipRect.rect().x(), clipRect.rect().y(), rect.maxX() - clipRect.rect().x(), rect.maxY() - clipRect.rect().y());
+            FloatRoundedRect::Radii topCornerRadii;
+            topCornerRadii.setTopLeft(clipRect.radii().topLeft());
+            clipDisplayItem->roundedRectClips().append(FloatRoundedRect(topCorner, topCornerRadii));
+
+            FloatRect bottomCorner(rect.x().toFloat(), rect.y().toFloat(), clipRect.rect().maxX() - rect.x().toFloat(), clipRect.rect().maxY() - rect.y().toFloat());
+            FloatRoundedRect::Radii bottomCornerRadii;
+            bottomCornerRadii.setBottomRight(clipRect.radii().bottomRight());
+            clipDisplayItem->roundedRectClips().append(FloatRoundedRect(bottomCorner, bottomCornerRadii));
+        }
+
+        if (!clipRect.radii().topRight().isEmpty() || !clipRect.radii().bottomLeft().isEmpty()) {
+            FloatRect topCorner(rect.x().toFloat(), clipRect.rect().y(), clipRect.rect().maxX() - rect.x().toFloat(), rect.maxY() - clipRect.rect().y());
+            FloatRoundedRect::Radii topCornerRadii;
+            topCornerRadii.setTopRight(clipRect.radii().topRight());
+            clipDisplayItem->roundedRectClips().append(FloatRoundedRect(topCorner, topCornerRadii));
+
+            FloatRect bottomCorner(clipRect.rect().x(), rect.y().toFloat(), rect.maxX() - clipRect.rect().x(), clipRect.rect().maxY() - rect.y().toFloat());
+            FloatRoundedRect::Radii bottomCornerRadii;
+            bottomCornerRadii.setBottomLeft(clipRect.radii().bottomLeft());
+            clipDisplayItem->roundedRectClips().append(FloatRoundedRect(bottomCorner, bottomCornerRadii));
+        }
+    }
+
+    if (m_useDisplayItemList) {
+        ASSERT(m_paintInfo.context->displayItemList());
+        m_paintInfo.context->displayItemList()->add(clipDisplayItem.release());
+    } else {
+        clipDisplayItem->replay(paintInfo.context);
+    }
+}
+
+RoundedInnerRectClipper::~RoundedInnerRectClipper()
+{
+    OwnPtr<EndClipDisplayItem> endClipDisplayItem = EndClipDisplayItem::create(m_renderer.displayItemClient());
+
+    if (m_useDisplayItemList) {
+        ASSERT(m_paintInfo.context->displayItemList());
+        m_paintInfo.context->displayItemList()->add(endClipDisplayItem.release());
+    } else {
+        endClipDisplayItem->replay(m_paintInfo.context);
+    }
+}
+
+} // namespace blink