Revert "Removed default Isolate."

src/d8.cc

 // Copyright 2012 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.
 
 
 // Defined when linking against shared lib on Windows.
 #if defined(USING_V8_SHARED) && !defined(V8_SHARED)
 #define V8_SHARED
 #endif
 
@@ skipping 1641 matching lines @@
   SetStandaloneFlagsViaCommandLine();
 #endif
   ShellArrayBufferAllocator array_buffer_allocator;
   MockArrayBufferAllocator mock_arraybuffer_allocator;
   if (options.mock_arraybuffer_allocator) {
     v8::V8::SetArrayBufferAllocator(&mock_arraybuffer_allocator);
   } else {
     v8::V8::SetArrayBufferAllocator(&array_buffer_allocator);
   }
   int result = 0;
-  Isolate* isolate = Isolate::New();
+  Isolate* isolate = Isolate::GetCurrent();
 #ifndef V8_SHARED
   v8::ResourceConstraints constraints;
   constraints.ConfigureDefaults(i::OS::TotalPhysicalMemory(),
                                 i::OS::MaxVirtualMemory(),
                                 i::CPU::NumberOfProcessorsOnline());
   v8::SetResourceConstraints(isolate, &constraints);
 #endif
   DumbLineEditor dumb_line_editor(isolate);
   {
-    Isolate::Scope scope(isolate);
     Initialize(isolate);
 #ifdef ENABLE_VTUNE_JIT_INTERFACE
     vTune::InitializeVtuneForV8();
 #endif
     PerIsolateData data(isolate);
     InitializeDebugger(isolate);
 
 #ifndef V8_SHARED
     if (options.dump_heap_constants) {
       DumpHeapConstants(reinterpret_cast<i::Isolate*>(isolate));
@@ skipping 58 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif