Add performance.now() to the d8 shell.

src/d8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 286 matching lines @@
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   static Handle<Object> DebugMessageDetails(Isolate* isolate,
                                             Handle<String> message);
   static Handle<Value> DebugCommandToJSONRequest(Isolate* isolate,
                                                  Handle<String> command);
   static void DispatchDebugMessages();
 #endif  // ENABLE_DEBUGGER_SUPPORT
 #endif  // V8_SHARED
 
+  static void WindowPerformanceNow(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmCurrent(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmOwner(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmGlobal(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmCreate(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmDispose(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmSwitch(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmEval(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RealmSharedGet(Local<String> property,
                              const  PropertyCallbackInfo<Value>& info);
   static void RealmSharedSet(Local<String> property,
@@ skipping 57 matching lines @@
   static void SetEnvironment(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void UnsetEnvironment(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetUMask(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void MakeDirectory(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void RemoveDirectory(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   static void AddOSMethods(Handle<ObjectTemplate> os_template);
 
   static const char* kPrompt;
   static ShellOptions options;
+  static const i::TimeTicks kInitialTicks;
 
  private:
   static Persistent<Context> evaluation_context_;
 #ifndef V8_SHARED
   static Persistent<Context> utility_context_;
   static CounterMap* counter_map_;
   // We statically allocate a set of local counters to be used if we
   // don't want to store the stats in a memory-mapped file
   static CounterCollection local_counters_;
   static CounterCollection* counters_;
@@ skipping 28 matching lines @@
   static void ExternalArrayWeakCallback(Isolate* isolate,
                                         Persistent<Object>* object,
                                         uint8_t* data);
 };
 
 
 }  // namespace v8
 
 
 #endif  // V8_D8_H_