[debugger] implement inspector-facing API for code coverage.

src/debug/debug-interface.h

 // Copyright 2016 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_INTERFACE_H_
 #define V8_DEBUG_DEBUG_INTERFACE_H_
 
 #include <functional>
 
 #include "include/v8-debug.h"
 #include "include/v8-util.h"
 #include "include/v8.h"
 
 #include "src/debug/interface-types.h"
+#include "src/globals.h"
 
 namespace v8 {
+
+namespace internal {
+struct CoverageRange;
+class Coverage;
+class Script;
+}
+
 namespace debug {
 
 /**
  * Debugger is running in its own context which is entered while debugger
  * messages are being dispatched. This is an explicit getter for this
  * debugger context. Note that the content of the debugger context is subject
  * to change. The Context exists only when the debugger is active, i.e. at
  * least one DebugEventListener or MessageHandler is set.
  */
 Local<Context> GetDebugContext(Isolate* isolate);
@@ skipping 164 matching lines @@
 class GeneratorObject {
  public:
   v8::MaybeLocal<debug::Script> Script();
   v8::Local<v8::Function> Function();
   debug::Location SuspendedLocation();
   bool IsSuspended();
 
   static v8::Local<debug::GeneratorObject> Cast(v8::Local<v8::Value> value);
 };
 
+/*
+ * Provide API layer between inspector and code coverage.
+ */
+class Coverage {
+ public:
+  class Range {
+   public:
+    // 0-based line and colum numbers.
+    Location Start() { return start_; }
+    Location End() { return end_; }
+    uint32_t Count();
+    size_t NestedCount();
+    Range GetNested(size_t i);
+    MaybeLocal<String> Name();
+
+   private:
+    Range(i::CoverageRange* range, Local<debug::Script> script);
+    i::CoverageRange* range_;
+    Location start_;
+    Location end_;
+    Local<debug::Script> script_;
+
+    friend class debug::Coverage;
+  };
+
+  V8_EXPORT_PRIVATE static Coverage Collect(Isolate* isolate);
+
+  V8_EXPORT_PRIVATE static void TogglePrecise(Isolate* isolate, bool enable);
+
+  size_t ScriptCount();
+  Local<debug::Script> GetScript(size_t i);
+  Range GetRange(size_t i);
+
+  ~Coverage();
+
+ private:
+  explicit Coverage(i::Coverage* coverage) : coverage_(coverage) {}
+  i::Coverage* coverage_;
+};
 }  // namespace debug
 }  // namespace v8
 
 #endif  // V8_DEBUG_DEBUG_INTERFACE_H_