Handle unicode correctly in CallPrinter

src/ast/prettyprinter.h

Index: src/ast/prettyprinter.h
diff --git a/src/ast/prettyprinter.h b/src/ast/prettyprinter.h
index 61a118d13644c1a3b2f19e3a8ceb01d2ebd7c4c3..a011e221b46b4fdef0dfdb8f16034dd3c64ef50f 100644
--- a/src/ast/prettyprinter.h
+++ b/src/ast/prettyprinter.h
@@ -8,6 +8,7 @@
 #include "src/allocation.h"
 #include "src/ast/ast.h"
 #include "src/base/compiler-specific.h"
+#include "src/string-builder.h"
 
 namespace v8 {
 namespace internal {
@@ -15,15 +16,10 @@ namespace internal {
 class CallPrinter final : public AstVisitor<CallPrinter> {
  public:
   explicit CallPrinter(Isolate* isolate, bool is_builtin);
-  ~CallPrinter();
 
   // The following routine prints the node with position |position| into a
-  // string. The result string is alive as long as the CallPrinter is alive.
-  const char* Print(FunctionLiteral* program, int position);
-
-  void PRINTF_FORMAT(2, 3) Print(const char* format, ...);
-
-  void Find(AstNode* node, bool print = false);
+  // string.
+  Handle<String> Print(FunctionLiteral* program, int position);
 
 // Individual nodes
 #define DECLARE_VISIT(type) void Visit##type(type* node);
@@ -31,11 +27,15 @@ class CallPrinter final : public AstVisitor<CallPrinter> {
 #undef DECLARE_VISIT
 
  private:
-  void Init();
+  // void PRINTF_FORMAT(2, 3) Print(const char* format, ...);
+  void Print(const char* str);
+  void Print(Handle<String> str);
+
+  void Find(AstNode* node, bool print = false);
+
   Isolate* isolate_;
-  char* output_;  // output string buffer
-  int size_;      // output_ size
-  int pos_;       // current printing position
+  int num_prints_;
+  IncrementalStringBuilder builder_;
   int position_;  // position of ast node to print
   bool found_;
   bool done_;