[debugger] add precise mode for code coverage.

src/debug/debug-coverage.h

 // Copyright 2017 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_DEBUG_DEBUG_COVERAGE_H_
 #define V8_DEBUG_DEBUG_COVERAGE_H_
 
 #include <vector>
 
 #include "src/allocation.h"
-#include "src/base/macros.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declaration.
 class Isolate;
 
 class Coverage : public AllStatic {
  public:
   struct RangeEntry {
     int end_position;
     uint32_t count;
   };
 
   struct ScriptData {
     ScriptData(int s, std::vector<RangeEntry> e)
         : script_id(s), entries(std::move(e)) {}
     int script_id;
     std::vector<RangeEntry> entries;
   };
 
   static std::vector<ScriptData> Collect(Isolate* isolate);
+
+  // Enable precise code coverage. This disables optimization and makes sure
+  // invocation count is not affected by GC.
+  static void EnablePrecise(Isolate* isolate);
+  static void DisablePrecise(Isolate* isolate);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_DEBUG_DEBUG_COVERAGE_H_