Use finer-grained checking in cold mode

third_party/WebKit/Source/core/editing/spellcheck/ColdModeSpellCheckRequester.h

Index: third_party/WebKit/Source/core/editing/spellcheck/ColdModeSpellCheckRequester.h
diff --git a/third_party/WebKit/Source/core/editing/spellcheck/ColdModeSpellCheckRequester.h b/third_party/WebKit/Source/core/editing/spellcheck/ColdModeSpellCheckRequester.h
index 113c4be7cfbf6e4a30ac050f5fc59dc01422d57c..5f7dc52e0e10633b68d7ad3abd540a25063b6eba 100644
--- a/third_party/WebKit/Source/core/editing/spellcheck/ColdModeSpellCheckRequester.h
+++ b/third_party/WebKit/Source/core/editing/spellcheck/ColdModeSpellCheckRequester.h
@@ -5,14 +5,12 @@
 #ifndef ColdModeSpellCheckRequester_h
 #define ColdModeSpellCheckRequester_h
 
+#include "core/editing/EphemeralRange.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
-class Element;
 class IdleDeadline;
-class LocalFrame;
-class Node;
 class SpellCheckRequester;
 
 // This class is only supposed to be used by IdleSpellCheckCallback in cold mode
@@ -36,10 +34,24 @@ class ColdModeSpellCheckRequester
   LocalFrame& frame() const { return *m_frame; }
   SpellCheckRequester& spellCheckRequester() const;
 
+  // Perform checking task incrementally based on the stored state.
+  void step();
+
+  void searchForNextRootEditable();
+  void initializeForCurrentRootEditable();
+  bool haveMoreChunksToCheck();
+  void requestCheckingForNextChunk();
+  void finishCheckingCurrentRootEditable();
+
+  void resetCheckingProgress();
   void chunkAndRequestFullCheckingFor(const Element&);
 
   const Member<LocalFrame> m_frame;
   Member<Node> m_nextNode;
+  Member<Element> m_currentRootEditable;
+  int m_currentFullLength;
+  int m_currentChunkIndex;
+  Position m_currentChunkStart;
   uint64_t m_lastCheckedDOMTreeVersion;
   mutable bool m_needsMoreInvocationForTesting;