Implement hot mode invocation for idle time spell checker

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

Index: third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.h
diff --git a/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.h b/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.h
index db1e34d49f2b9e952e397da3c15dcdcc17755b47..fa015c47a9ecfd7521547be18cc51df69c38a772 100644
--- a/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.h
+++ b/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.h
@@ -7,6 +7,8 @@
 
 #include "core/dom/IdleRequestCallback.h"
 #include "core/dom/SynchronousMutationObserver.h"
+#include "core/editing/EphemeralRange.h"
+#include "core/editing/Position.h"
 #include "platform/Timer.h"
 
 namespace blink {
@@ -70,6 +72,13 @@ class CORE_EXPORT IdleSpellCheckCallback final
   void requestInvocation();
 
   // Functions for hot mode.
+  bool isTypingInPartialWord(const Element&) const;
+  bool shouldCheckRootEditableInHotMode(const Element&, const Position&) const;
+  EphemeralRange calculateHotModeCheckingRange(const Element&,
+                                               const Position&) const;
+  void checkRootEditableInHotMode(Element*,
+                                  const Position&,
+                                  HeapVector<Member<Element>>*);
   void hotModeInvocation(IdleDeadline*);
 
   // Transit to ColdModeTimerStarted, if possible. Sets up a timer, and requests
@@ -88,7 +97,7 @@ class CORE_EXPORT IdleSpellCheckCallback final
   int m_idleCallbackHandle;
   mutable bool m_needsMoreColdModeInvocationForTesting;
   const Member<LocalFrame> m_frame;
-
+  uint64_t m_lastProcessedUndoStepSequence;
   TaskRunnerTimer<IdleSpellCheckCallback> m_coldModeTimer;
 };