[debugger] add precise mode for code coverage.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index d54654f9c6f607c30b9d0b73718c0bf4e5e7ead8..afe09ba08bc3b14865d241898d2311b5f38b4998 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2901,10 +2901,9 @@ Map* Isolate::get_initial_js_array_map(ElementsKind kind) {
   return nullptr;
 }
 
-
-bool Isolate::use_crankshaft() const {
+bool Isolate::use_crankshaft() {
   return FLAG_opt && FLAG_crankshaft && !serializer_enabled_ &&
-         CpuFeatures::SupportsCrankshaft();
+         CpuFeatures::SupportsCrankshaft() && !IsCodeCoverageEnabled();
 }
 
 bool Isolate::NeedsSourcePositionsForProfiling() const {
@@ -2913,6 +2912,15 @@ 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);
+}
+
 bool Isolate::IsArrayOrObjectPrototype(Object* object) {
   Object* context = heap()->native_contexts_list();
   while (!context->IsUndefined(this)) {