Create libsampler as V8 sampler library.

test/cctest/test-cpu-profiler.cc

 // Copyright 2010 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 404 matching lines @@
                                    v8::Local<v8::Value> argv[], int argc,
                                    unsigned min_js_samples = 0,
                                    unsigned min_external_samples = 0,
                                    bool collect_samples = false) {
   v8::CpuProfiler* cpu_profiler = env->GetIsolate()->GetCpuProfiler();
   v8::Local<v8::String> profile_name = v8_str("my_profile");
 
   cpu_profiler->SetSamplingInterval(100);
   cpu_profiler->StartProfiling(profile_name, collect_samples);
 
-  i::Sampler* sampler =
+  v8::sampler::Sampler* sampler =
       reinterpret_cast<i::Isolate*>(env->GetIsolate())->logger()->sampler();
   sampler->StartCountingSamples();
   do {
     function->Call(env, env->Global(), argc, argv).ToLocalChecked();
   } while (sampler->js_sample_count() < min_js_samples ||
            sampler->external_sample_count() < min_external_samples);
 
   v8::CpuProfile* profile = cpu_profiler->StopProfiling(profile_name);
 
   CHECK(profile);
@@ skipping 1587 matching lines @@
   iprofile->Print();
   v8::CpuProfile* profile = reinterpret_cast<v8::CpuProfile*>(iprofile);
 
   const char* branch[] = {"", "test"};
   const ProfileNode* itest_node =
       GetSimpleBranch(env, profile, branch, arraysize(branch));
   CHECK_EQ(0U, itest_node->deopt_infos().size());
 
   iprofiler->DeleteProfile(iprofile);
 }