Allow certain SP recorder classes to defer their "begin" operation.

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
index 5f4274cc6bdedd8a7e88c758d4c57acecfb6c2de..b9f8484ee71b96fa74190a30f21f41b10e5102d8 100644
--- a/Source/core/paint/RoundedInnerRectClipper.cpp
+++ b/Source/core/paint/RoundedInnerRectClipper.cpp
@@ -12,13 +12,48 @@
 
 namespace blink {
 
-RoundedInnerRectClipper::RoundedInnerRectClipper(LayoutObject& layoutObject, const PaintInfo& paintInfo, const LayoutRect& rect, const FloatRoundedRect& clipRect, RoundedInnerRectClipperBehavior behavior)
+RoundedInnerRectClipper::RoundedInnerRectClipper(LayoutObject& layoutObject, const PaintInfo& paintInfo)
     : m_layoutObject(layoutObject)
     , m_paintInfo(paintInfo)
-    , m_useDisplayItemList(RuntimeEnabledFeatures::slimmingPaintEnabled() && behavior == ApplyToDisplayListIfEnabled)
-    , m_clipType(m_useDisplayItemList ? m_paintInfo.displayItemTypeForClipping() : DisplayItem::ClipBoxPaintPhaseFirst)
+    , m_useDisplayItemList(false)
+    , m_clipType(DisplayItem::ClipBoxPaintPhaseFirst)
+    , m_engaged(false)
+{
+}
+
+RoundedInnerRectClipper::RoundedInnerRectClipper(LayoutObject& layoutObject, const PaintInfo& paintInfo, const LayoutRect& rect, const FloatRoundedRect& clipRect, RoundedInnerRectClipperBehavior behavior)
+    : RoundedInnerRectClipper(layoutObject, paintInfo)
 {
-    OwnPtr<ClipDisplayItem> clipDisplayItem = ClipDisplayItem::create(layoutObject, m_clipType, LayoutRect::infiniteIntRect());
+    begin(rect, clipRect, behavior);
+}
+
+RoundedInnerRectClipper::~RoundedInnerRectClipper()
+{
+    if (!m_engaged)
+        return;
+
+    DisplayItem::Type endType = DisplayItem::clipTypeToEndClipType(m_clipType);
+    if (m_useDisplayItemList) {
+        ASSERT(m_paintInfo.context->displayItemList());
+        if (m_paintInfo.context->displayItemList()->displayItemConstructionIsDisabled())
+            return;
+        OwnPtr<EndClipDisplayItem> endClipDisplayItem = EndClipDisplayItem::create(m_layoutObject, endType);
+        m_paintInfo.context->displayItemList()->add(endClipDisplayItem.release());
+    } else {
+        EndClipDisplayItem endClipDisplayItem(m_layoutObject, endType);
+        endClipDisplayItem.replay(*m_paintInfo.context);
+    }
+}
+
+void RoundedInnerRectClipper::begin(const LayoutRect& rect, const FloatRoundedRect& clipRect, RoundedInnerRectClipperBehavior behavior)
+{
+    ASSERT(!m_engaged);
+    m_engaged = true;
+
+    m_useDisplayItemList = RuntimeEnabledFeatures::slimmingPaintEnabled() && behavior == ApplyToDisplayListIfEnabled;
+    m_clipType = m_useDisplayItemList ? m_paintInfo.displayItemTypeForClipping() : DisplayItem::ClipBoxPaintPhaseFirst;
+
+    OwnPtr<ClipDisplayItem> clipDisplayItem = ClipDisplayItem::create(m_layoutObject, m_clipType, LayoutRect::infiniteIntRect());
 
     if (clipRect.isRenderable()) {
         clipDisplayItem->roundedRectClips().append(clipRect);
@@ -55,22 +90,7 @@ RoundedInnerRectClipper::RoundedInnerRectClipper(LayoutObject& layoutObject, con
             return;
         m_paintInfo.context->displayItemList()->add(clipDisplayItem.release());
     } else {
-        clipDisplayItem->replay(*paintInfo.context);
-    }
-}
-
-RoundedInnerRectClipper::~RoundedInnerRectClipper()
-{
-    DisplayItem::Type endType = DisplayItem::clipTypeToEndClipType(m_clipType);
-    if (m_useDisplayItemList) {
-        ASSERT(m_paintInfo.context->displayItemList());
-        if (m_paintInfo.context->displayItemList()->displayItemConstructionIsDisabled())
-            return;
-        OwnPtr<EndClipDisplayItem> endClipDisplayItem = EndClipDisplayItem::create(m_layoutObject, endType);
-        m_paintInfo.context->displayItemList()->add(endClipDisplayItem.release());
-    } else {
-        EndClipDisplayItem endClipDisplayItem(m_layoutObject, endType);
-        endClipDisplayItem.replay(*m_paintInfo.context);
+        clipDisplayItem->replay(*m_paintInfo.context);
     }
 }