Disable display item caching

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
index f4723e3b27c2f291c80104e8df8da8ae8adc2f5c..32789455cd6c2b84e61ed00c9cbd691e054695a9 100644
--- a/Source/platform/graphics/paint/DisplayItemList.cpp
+++ b/Source/platform/graphics/paint/DisplayItemList.cpp
@@ -15,11 +15,26 @@
 
 namespace blink {
 
-const PaintList& DisplayItemList::paintList()
+void DisplayItemList::beginNewPaints()
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
+    ASSERT(!m_newPaints.size());
+    ASSERT(!m_doingNewPaints);
+    m_doingNewPaints = true;
+}
 
+void DisplayItemList::endNewPaints()
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
+    ASSERT(m_doingNewPaints);
+    m_doingNewPaints = false;
     updatePaintList();
+}
+
+const PaintList& DisplayItemList::paintList()
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
+    ASSERT(!m_doingNewPaints);
     return m_paintList;
 }
 
@@ -39,11 +54,16 @@ void DisplayItemList::invalidateAll()
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
     // Can only be called during layout/paintInvalidation, not during painting.
-    ASSERT(m_newPaints.isEmpty());
+    ASSERT(!m_doingNewPaints && m_newPaints.isEmpty());

[chrishtr, 2015/01/20 23:18:53]

Looks like m_doingNewPaints is only used in ASSERTs? Is it really necessary?

[Xianzhu, 2015/01/20 23:48:11]

It was to ensure beginNewPaints() and endNewPaints() are paired. beginNewPaints
and the flag seem not necessary. Removed them and keep endNewPaints() only.

     m_paintList.clear();
     m_cachedClients.clear();
 }
 
+bool DisplayItemList::clientCacheIsValid(DisplayItemClient client) const
+{
+    return RuntimeEnabledFeatures::slimmingPaintDisplayItemCacheEnabled() && m_cachedClients.contains(client);
+}
+
 PaintList::iterator DisplayItemList::findNextMatchingCachedItem(PaintList::iterator begin, const DisplayItem& displayItem)
 {
     PaintList::iterator end = m_paintList.end();
@@ -74,6 +94,13 @@ static void appendDisplayItem(PaintList& list, HashSet<DisplayItemClient>& clien
 // the ordering implied by the existing paint list, extra treewalks are avoided.
 void DisplayItemList::updatePaintList()
 {
+    if (!RuntimeEnabledFeatures::slimmingPaintDisplayItemCacheEnabled()) {
+        m_paintList.clear();
+        m_paintList.swap(m_newPaints);
+        m_cachedClients.clear();
+        return;
+    }
+
     PaintList updatedList;
     HashSet<DisplayItemClient> newCachedClients;