Allow CpuProfiler::SetIdle to be called while executing JS.

This could be the case when running nested message loop
while paused in debugger.

BUG=none
LOG=N

Review-Url: https://codereview.chromium.org/1922703005
Cr-Commit-Position: refs/heads/master@{#35880}

src/api.cc

@@ -8354,7 +8354,7 @@ CpuProfile* CpuProfiler::StopProfiling(Local<String> title) {
 void CpuProfiler::SetIdle(bool is_idle) {
   i::Isolate* isolate = reinterpret_cast<i::CpuProfiler*>(this)->isolate();
   v8::StateTag state = isolate->current_vm_state();
-  DCHECK(state == v8::EXTERNAL || state == v8::IDLE);
+  DCHECK(state == v8::JS || state == v8::EXTERNAL || state == v8::IDLE);
   if (isolate->js_entry_sp() != NULL) return;
   if (is_idle) {
     isolate->set_current_vm_state(v8::IDLE);