Remove dependencies of V8 on cpu-profiler is_profiling.

src/profiler/cpu-profiler.cc

Index: src/profiler/cpu-profiler.cc
diff --git a/src/profiler/cpu-profiler.cc b/src/profiler/cpu-profiler.cc
index dbd0434b0aa4852d8863651b8ad647175996a268..2da286cb7f5194a4065c7cc807399461ef3850a9 100644
--- a/src/profiler/cpu-profiler.cc
+++ b/src/profiler/cpu-profiler.cc
@@ -570,6 +570,7 @@ void CpuProfiler::StartProcessorIfNotStarted() {
   processor_ = new ProfilerEventsProcessor(
       generator_, sampler, sampling_interval_);
   is_profiling_ = true;
+  isolate_->set_is_profiling(true);
   // Enumerate stuff we already have in the heap.
   DCHECK(isolate_->heap()->HasBeenSetUp());
   if (!FLAG_prof_browser_mode) {
@@ -615,6 +616,7 @@ void CpuProfiler::StopProcessor() {
   sampler::Sampler* sampler =
       reinterpret_cast<sampler::Sampler*>(logger->ticker_);
   is_profiling_ = false;
+  isolate_->set_is_profiling(false);
   processor_->StopSynchronously();
   delete processor_;
   delete generator_;