Hide cold mode idle time spellchecker behind a flag

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

Index: third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp
diff --git a/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp b/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp
index b28309ebeed9352f91ee3aba4504281b2222d1f1..41211b259bc2165bbe308c0610578816aa8d4a08 100644
--- a/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp
+++ b/third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp
@@ -103,7 +103,8 @@ void IdleSpellCheckCallback::SetNeedsInvocation() {
 }
 
 void IdleSpellCheckCallback::SetNeedsColdModeInvocation() {
-  if (!IsSpellCheckingEnabled()) {
+  if (!RuntimeEnabledFeatures::idleTimeColdModeSpellCheckingEnabled() ||
+      !IsSpellCheckingEnabled()) {
     Deactivate();
     return;
   }
@@ -121,6 +122,7 @@ void IdleSpellCheckCallback::SetNeedsColdModeInvocation() {
 }
 
 void IdleSpellCheckCallback::ColdModeTimerFired(TimerBase*) {
+  DCHECK(RuntimeEnabledFeatures::idleTimeColdModeSpellCheckingEnabled());
   DCHECK_EQ(State::kColdModeTimerStarted, state_);
 
   if (!IsSpellCheckingEnabled()) {
@@ -174,6 +176,7 @@ void IdleSpellCheckCallback::handleEvent(IdleDeadline* deadline) {
     HotModeInvocation(deadline);
     SetNeedsColdModeInvocation();
   } else if (state_ == State::kColdModeRequested) {
+    DCHECK(RuntimeEnabledFeatures::idleTimeColdModeSpellCheckingEnabled());
     state_ = State::kInColdModeInvocation;
     cold_mode_requester_->Invoke(deadline);
     if (cold_mode_requester_->FullDocumentChecked())