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

Source/core/paint/RoundedInnerRectClipper.cpp

 // 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/layout/LayoutBox.h"
 #include "core/paint/PaintInfo.h"
 #include "platform/graphics/paint/ClipDisplayItem.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 
 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)
 {
-    OwnPtr<ClipDisplayItem> clipDisplayItem = ClipDisplayItem::create(layoutObject, m_clipType, LayoutRect::infiniteIntRect());
+}
+
+RoundedInnerRectClipper::RoundedInnerRectClipper(LayoutObject& layoutObject, const PaintInfo& paintInfo, const LayoutRect& rect, const FloatRoundedRect& clipRect, RoundedInnerRectClipperBehavior behavior)
+    : RoundedInnerRectClipper(layoutObject, paintInfo)
+{
+    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);
     } 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));
@@ skipping 16 matching lines @@
             clipDisplayItem->roundedRectClips().append(FloatRoundedRect(bottomCorner, bottomCornerRadii));
         }
     }
 
     if (m_useDisplayItemList) {
         ASSERT(m_paintInfo.context->displayItemList());
         if (m_paintInfo.context->displayItemList()->displayItemConstructionIsDisabled())
             return;
         m_paintInfo.context->displayItemList()->add(clipDisplayItem.release());
     } else {
-        clipDisplayItem->replay(*paintInfo.context);
+        clipDisplayItem->replay(*m_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);
-    }
-}
-
 } // namespace blink