Revert "Removed default Isolate."

test/cctest/test-api.cc

 // 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 19251 matching lines @@
   // Reset the failed access check callback so it does not influence
   // the other tests.
   v8::V8::SetFailedAccessCheckCallbackFunction(NULL);
 }
 
 
 TEST(IsolateNewDispose) {
   v8::Isolate* current_isolate = CcTest::isolate();
   v8::Isolate* isolate = v8::Isolate::New();
   CHECK(isolate != NULL);
+  CHECK(!reinterpret_cast<i::Isolate*>(isolate)->IsDefaultIsolate());
   CHECK(current_isolate != isolate);
   CHECK(current_isolate == CcTest::isolate());
 
   v8::V8::SetFatalErrorHandler(StoringErrorCallback);
   last_location = last_message = NULL;
   isolate->Dispose();
   CHECK_EQ(last_location, NULL);
   CHECK_EQ(last_message, NULL);
 }
 
@@ skipping 3049 matching lines @@
   CHECK_EQ("V8.Test", last_event_message);
   CHECK_EQ(0, last_event_status);
   histogramTimer->Stop();
   CHECK_EQ("V8.Test", last_event_message);
   CHECK_EQ(1, last_event_status);
 }
 
 
 TEST(Promises) {
   i::FLAG_harmony_promises = true;
-  i::FLAG_harmony_weak_collections = true;  // Implied
 
   LocalContext context;
   v8::Isolate* isolate = context->GetIsolate();
   v8::HandleScope scope(isolate);
   Handle<Object> global = context->Global();
 
   // Creation.
   Handle<v8::Promise::Resolver> pr = v8::Promise::Resolver::New(isolate);
   Handle<v8::Promise::Resolver> rr = v8::Promise::Resolver::New(isolate);
   Handle<v8::Promise> p = pr->GetPromise();
@@ skipping 166 matching lines @@
   v8::internal::FLAG_stack_size = 150;
   LocalContext current;
   v8::Isolate* isolate = current->GetIsolate();
   v8::HandleScope scope(isolate);
   V8::SetCaptureStackTraceForUncaughtExceptions(
       true, 10, v8::StackTrace::kDetailed);
   v8::TryCatch try_catch;
   CompileRun("(function f(x) { f(x+1); })(0)");
   CHECK(try_catch.HasCaught());
 }