StringTable::LookupKey() and all callers handlified.

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 17976 matching lines @@
       env->GetIsolate(), string, v8::String::kInternalizedString);
   CHECK(string2->MakeExternal(resource[2]));
 
   // Symbolized External.
   resource[3] = new TestResource(AsciiToTwoByteString("Some other string"));
   v8::Local<v8::String> string3 =
       v8::String::NewExternal(env->GetIsolate(), resource[3]);
   CcTest::heap()->CollectAllAvailableGarbage();  // Tenure string.
   // Turn into a symbol.
   i::Handle<i::String> string3_i = v8::Utils::OpenHandle(*string3);
-  CHECK(!CcTest::heap()->InternalizeString(*string3_i)->IsFailure());
+  CHECK(!CcTest::i_isolate()->factory()->InternalizeString(
+      string3_i).is_null());
   CHECK(string3_i->IsInternalizedString());
 
   // We need to add usages for string* to avoid warnings in GCC 4.7
   CHECK(string0->IsExternal());
   CHECK(string1->IsExternal());
   CHECK(string2->IsExternal());
   CHECK(string3->IsExternal());
 
   VisitorImpl visitor(resource);
   v8::V8::VisitExternalResources(&visitor);
@@ skipping 4484 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());
 }