Move ViewDisplayList to GraphicsLayer

Source/platform/graphics/paint/DisplayItemList.cpp

Index: Source/platform/graphics/paint/DisplayItemList.cpp
diff --git a/Source/platform/graphics/paint/DisplayItemList.cpp b/Source/platform/graphics/paint/DisplayItemList.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..3e9268525a9cec15b06dd15dd1edba975627d3d3
--- /dev/null
+++ b/Source/platform/graphics/paint/DisplayItemList.cpp
@@ -0,0 +1,136 @@
+// 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 "platform/graphics/paint/DisplayItemList.h"
+
+#include "platform/NotImplemented.h"
+#include "platform/RuntimeEnabledFeatures.h"
+#ifndef NDEBUG
+#include "platform/graphics/paint/DisplayItem.h"
+#include "wtf/text/StringBuilder.h"
+#endif
+
+namespace blink {
+
+const PaintList& DisplayItemList::paintList()
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
+
+    updatePaintList();
+    return m_paintList;
+}
+
+void DisplayItemList::add(WTF::PassOwnPtr<DisplayItem> displayItem)
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
+    m_newPaints.append(displayItem);
+}
+
+void DisplayItemList::invalidate(DisplayItemClient renderer)
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
+    m_invalidated.add(renderer);
+}
+
+PaintList::iterator DisplayItemList::findDisplayItem(PaintList::iterator begin, const DisplayItem& displayItem)
+{
+    PaintList::iterator end = m_paintList.end();
+    if (displayItem.client() && !m_paintListRenderers.contains(displayItem.client()))
+        return end;
+
+    for (PaintList::iterator it = begin; it != end; ++it) {
+        DisplayItem& existing = **it;
+        if (existing.idsEqual(displayItem))
+            return it;
+    }
+
+    // FIXME: Properly handle clips.
+    ASSERT(!displayItem.client());
+    return end;
+}
+
+bool DisplayItemList::wasInvalidated(const DisplayItem& displayItem) const
+{
+    // FIXME: Use a bit on DisplayItemClient instead of tracking m_invalidated.
+    return displayItem.client() && m_invalidated.contains(displayItem.client());
+}
+
+static void appendDisplayItem(PaintList& list, HashSet<DisplayItemClient>& renderers, WTF::PassOwnPtr<DisplayItem> displayItem)
+{
+    if (DisplayItemClient renderer = displayItem->client())
+        renderers.add(renderer);
+    list.append(displayItem);
+}
+
+// Update the existing paintList by removing invalidated entries, updating
+// repainted ones, and appending new items.
+//
+// The algorithm is O(|existing paint list| + |newly painted list|): by using
+// the ordering implied by the existing paint list, extra treewalks are avoided.
+void DisplayItemList::updatePaintList()
+{
+    PaintList updatedList;
+    HashSet<DisplayItemClient> updatedRenderers;
+
+    if (int maxCapacity = m_newPaints.size() + std::max(0, (int)m_paintList.size() - (int)m_invalidated.size()))
+        updatedList.reserveCapacity(maxCapacity);
+
+    PaintList::iterator paintListIt = m_paintList.begin();
+    PaintList::iterator paintListEnd = m_paintList.end();
+
+    for (OwnPtr<DisplayItem>& newDisplayItem : m_newPaints) {
+        if (!wasInvalidated(*newDisplayItem)) {
+            PaintList::iterator repaintIt = findDisplayItem(paintListIt, *newDisplayItem);
+            if (repaintIt != paintListEnd) {
+                // Copy all of the existing items over until we hit the repaint.
+                for (; paintListIt != repaintIt; ++paintListIt) {
+                    if (!wasInvalidated(**paintListIt))
+                        appendDisplayItem(updatedList, updatedRenderers, paintListIt->release());
+                }
+                paintListIt++;
+            }
+        }
+        // Copy over the new item.
+        appendDisplayItem(updatedList, updatedRenderers, newDisplayItem.release());
+    }
+
+    // Copy over any remaining items that were not invalidated.
+    for (; paintListIt != paintListEnd; ++paintListIt) {
+        if (!wasInvalidated(**paintListIt))
+            appendDisplayItem(updatedList, updatedRenderers, paintListIt->release());
+    }
+
+    m_invalidated.clear();
+    m_newPaints.clear();
+    m_paintList.clear();
+    m_paintList.swap(updatedList);
+    m_paintListRenderers.clear();
+    m_paintListRenderers.swap(updatedRenderers);
+}
+
+#ifndef NDEBUG
+
+static WTF::String paintListAsDebugString(const PaintList& list)
+{
+    StringBuilder stringBuilder;
+    bool isFirst = true;
+    for (auto& displayItem : list) {
+        if (!isFirst)
+            stringBuilder.append(", ");
+        isFirst = false;
+        stringBuilder.append(displayItem->asDebugString());
+    }
+    return stringBuilder.toString();
+}
+
+void DisplayItemList::showDebugData() const
+{
+    fprintf(stderr, "paint list: [%s]\n", paintListAsDebugString(m_paintList).utf8().data());
+    fprintf(stderr, "new paints: [%s]\n", paintListAsDebugString(m_newPaints).utf8().data());
+}
+
+#endif
+
+} // namespace blink