[debug] refactor code coverage to use enum for mode.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 1332ad0c71c6ad7f0e5c41abee864f73acc682f1..eded6d0bab27d76d14341a0b680f2cfe317d835d 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2990,7 +2990,7 @@ Map* Isolate::get_initial_js_array_map(ElementsKind kind) {
 
 bool Isolate::use_crankshaft() {
   return FLAG_opt && FLAG_crankshaft && !serializer_enabled_ &&
-         CpuFeatures::SupportsCrankshaft() && !IsCodeCoverageEnabled();
+         CpuFeatures::SupportsCrankshaft() && !is_precise_count_code_coverage();
 }
 
 bool Isolate::NeedsSourcePositionsForProfiling() const {
@@ -2999,10 +2999,6 @@ bool Isolate::NeedsSourcePositionsForProfiling() const {
          debug_->is_active() || logger_->is_logging();
 }
 
-bool Isolate::IsCodeCoverageEnabled() {
-  return heap()->code_coverage_list()->IsArrayList();
-}
-
 void Isolate::SetCodeCoverageList(Object* value) {
   DCHECK(value->IsUndefined(this) || value->IsArrayList());
   heap()->set_code_coverage_list(value);