vmservice: Add /coverage collection to scripts, classes and libraries.

runtime/vm/coverage.h

Index: runtime/vm/coverage.h
diff --git a/runtime/vm/coverage.h b/runtime/vm/coverage.h
index 7cc82228111c2bae0cd59a0ece03d03817f2023a..a316a68fa14c243e59af97fc6a2137f7e02f273f 100644
--- a/runtime/vm/coverage.h
+++ b/runtime/vm/coverage.h
@@ -19,14 +19,23 @@ template <typename T> class GrowableArray;
 class Isolate;
 class JSONArray;
 class JSONStream;
+class Library;
+class Script;
+class String;
 
 class CodeCoverage : public AllStatic {
  public:
   static void Write(Isolate* isolate);
   static void PrintJSON(Isolate* isolate, JSONStream* stream);
 
+  static void PrintJSONForScript(const String& script_name, JSONStream* stream);
+  static void PrintJSONForLibrary(const Library& lib, JSONStream* stream);
+  static void PrintJSONForClass(const Class& lib, JSONStream* stream);
+
  private:
-  static void PrintClass(const Class& cls, const JSONArray& arr);
+  static void PrintClass(const Class& cls,
+                         const JSONArray& arr,
+                         const Script& script_filter);
   static void CompileAndAdd(const Function& function,
                             const JSONArray& hits_arr,
                             const GrowableArray<intptr_t>& pos_to_line);