[Tracing] Implement IC statistics in tracing.

src/type-hints.h

 // Copyright 2015 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_TYPE_HINTS_H_
 #define V8_TYPE_HINTS_H_
 
 #include "src/base/flags.h"
 #include "src/utils.h"
 
@@ skipping 44 matching lines @@
   kSymbol = 1u << 6,
   kHeapNumber = 1u << 7,
   kSimdValue = 1u << 8,
   kAny = kUndefined | kBoolean | kNull | kSmallInteger | kReceiver | kString |
          kSymbol | kHeapNumber | kSimdValue,
   kNeedsMap = kReceiver | kString | kSymbol | kHeapNumber | kSimdValue,
   kCanBeUndetectable = kReceiver,
 };
 
 std::ostream& operator<<(std::ostream&, ToBooleanHint);
+std::string ToString(ToBooleanHint);
 
 typedef base::Flags<ToBooleanHint, uint16_t> ToBooleanHints;
 
 std::ostream& operator<<(std::ostream&, ToBooleanHints);
+std::string ToString(ToBooleanHints);
 
 DEFINE_OPERATORS_FOR_FLAGS(ToBooleanHints)
 
 enum StringAddFlags {
   // Omit both parameter checks.
   STRING_ADD_CHECK_NONE = 0,
   // Check left parameter.
   STRING_ADD_CHECK_LEFT = 1 << 0,
   // Check right parameter.
   STRING_ADD_CHECK_RIGHT = 1 << 1,
   // Check both parameters.
   STRING_ADD_CHECK_BOTH = STRING_ADD_CHECK_LEFT | STRING_ADD_CHECK_RIGHT,
   // Convert parameters when check fails (instead of throwing an exception).
   STRING_ADD_CONVERT = 1 << 2,
   STRING_ADD_CONVERT_LEFT = STRING_ADD_CHECK_LEFT | STRING_ADD_CONVERT,
   STRING_ADD_CONVERT_RIGHT = STRING_ADD_CHECK_RIGHT | STRING_ADD_CONVERT
 };
 
 std::ostream& operator<<(std::ostream& os, const StringAddFlags& flags);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TYPE_HINTS_H_