Revert of Remove begin/end subseq. display items, and store on PaintController instead.

third_party/WebKit/Source/platform/graphics/paint/PaintController.h

Index: third_party/WebKit/Source/platform/graphics/paint/PaintController.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/PaintController.h b/third_party/WebKit/Source/platform/graphics/paint/PaintController.h
index 2fdedcadec122cc7de825f9d9fdf7f69f78c60a5..c4a237b1d6e75eaea937d0f397127885b4298220 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/PaintController.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/PaintController.h
@@ -109,11 +109,8 @@
   // true. Otherwise returns false.
   bool useCachedSubsequenceIfPossible(const DisplayItemClient&);
 
-  void addCachedSubsequence(const DisplayItemClient&,
-                            unsigned start,
-                            unsigned end);
-
   // True if the last display item is a begin that doesn't draw content.
+  bool lastDisplayItemIsNoopBegin() const;
   void removeLastDisplayItem();
   const DisplayItem* lastDisplayItem(unsigned offset);
 
@@ -196,17 +193,6 @@
   paintChunksRasterInvalidationTrackingMap() {
     return m_paintChunksRasterInvalidationTrackingMap.get();
   }
-
-#if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
-  void beginShouldKeepAlive(const DisplayItemClient&);
-
-  void beginSubsequence(const DisplayItemClient& client) {
-    m_currentSubsequenceClients.push_back(&client);
-    beginShouldKeepAlive(client);
-  }
-
-  void endSubsequence() { m_currentSubsequenceClients.pop_back(); }
-#endif
 
  protected:
   PaintController()
@@ -218,14 +204,14 @@
         m_imagePainted(false),
         m_skippingCacheCount(0),
         m_numCachedNewItems(0),
-        m_currentCachedSubsequenceBeginIndexInNewList(kNotFound),
+        m_currentCachedSubsequenceBeginIndexInNewList(kNotFound)
 #ifndef NDEBUG
+        ,
         m_numSequentialMatches(0),
         m_numOutOfOrderMatches(0),
-        m_numIndexedItems(0),
-#endif
-        m_underInvalidationCheckingBegin(0),
-        m_underInvalidationCheckingEnd(0) {
+        m_numIndexedItems(0)
+#endif
+  {
     resetCurrentListIndices();
     setTracksRasterInvalidations(
         RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled());
@@ -234,8 +220,6 @@
  private:
   friend class PaintControllerTestBase;
   friend class PaintControllerPaintTestBase;
-
-  bool lastDisplayItemIsNoopBegin() const;
 
   void ensureNewDisplayItemListInitialCapacity() {
     if (m_newDisplayItemList.isEmpty()) {
@@ -268,7 +252,7 @@
 
   size_t findCachedItem(const DisplayItem::Id&);
   size_t findOutOfOrderCachedItemForward(const DisplayItem::Id&);
-  void copyCachedSubsequence(size_t beginIndex, size_t endIndex);
+  void copyCachedSubsequence(size_t&);
 
   // Resets the indices (e.g. m_nextItemToMatch) of
   // m_currentPaintArtifact.getDisplayItemList() to their initial values. This
@@ -289,29 +273,11 @@
   void showUnderInvalidationError(const char* reason,
                                   const DisplayItem& newItem,
                                   const DisplayItem* oldItem) const;
-
-  void showSequenceUnderInvalidationError(const char* reason,
-                                          const DisplayItemClient&,
-                                          int start,
-                                          int end);
-
   void checkUnderInvalidation();
   bool isCheckingUnderInvalidation() const {
     return m_underInvalidationCheckingEnd - m_underInvalidationCheckingBegin >
            0;
   }
-
-  struct SubsequenceMarkers {
-    SubsequenceMarkers() : start(0), end(0) {}
-    SubsequenceMarkers(size_t startArg, size_t endArg)
-        : start(startArg), end(endArg) {}
-    // The start and end index within m_currentPaintArtifact of this
-    // subsequence.
-    size_t start;
-    size_t end;
-  };
-
-  SubsequenceMarkers* getSubsequenceMarkers(const DisplayItemClient&);
 
   // The last complete paint artifact.
   // In SPv2, this includes paint chunks as well as display items.
@@ -412,14 +378,6 @@
   // A stack recording subsequence clients that are currently painting.
   Vector<const DisplayItemClient*> m_currentSubsequenceClients;
 #endif
-
-  typedef HashMap<const DisplayItemClient*, SubsequenceMarkers>
-      CachedSubsequenceMap;
-  CachedSubsequenceMap m_currentCachedSubsequences;
-  CachedSubsequenceMap m_newCachedSubsequences;
-
-  FRIEND_TEST_ALL_PREFIXES(PaintControllerTest, CachedSubsequenceSwapOrder);
-  FRIEND_TEST_ALL_PREFIXES(PaintControllerTest, CachedNestedSubsequenceUpdate);
 };
 
 }  // namespace blink