Remove runtime-call-stats from compiler dispatcher

RCS can't be used on background threads out of the box, but ignition
already has RCS itself, so just do trace events

BUG=v8:5215
R=rmcilroy@chromium.org

Review-Url: https://codereview.chromium.org/2602383002
Cr-Commit-Position: refs/heads/master@{#42032}

src/compiler-dispatcher/compiler-dispatcher-tracer.cc

@@ -24,11 +24,6 @@ CompilerDispatcherTracer::Scope::Scope(CompilerDispatcherTracer* tracer,
                                        ScopeID scope_id, size_t num)
     : tracer_(tracer), scope_id_(scope_id), num_(num) {
   start_time_ = MonotonicallyIncreasingTimeInMs();
-  // TODO(cbruni): remove once we fully moved to a trace-based system.
-  if (V8_UNLIKELY(FLAG_runtime_stats)) {
-    RuntimeCallStats::Enter(tracer_->runtime_call_stats_, &timer_,
-                            &RuntimeCallStats::CompilerDispatcher);
-  }
 }
 
 CompilerDispatcherTracer::Scope::~Scope() {
@@ -53,10 +48,6 @@ CompilerDispatcherTracer::Scope::~Scope() {
       tracer_->RecordFinalizeCompiling(elapsed);
       break;
   }
-  // TODO(cbruni): remove once we fully moved to a trace-based system.
-  if (V8_UNLIKELY(FLAG_runtime_stats)) {
-    RuntimeCallStats::Leave(tracer_->runtime_call_stats_, &timer_);
-  }
 }
 
 // static

src/compiler-dispatcher/compiler-dispatcher-tracer.h

@@ -52,7 +52,6 @@ class V8_EXPORT_PRIVATE CompilerDispatcherTracer {
     ScopeID scope_id_;
     size_t num_;
     double start_time_;
-    RuntimeCallTimer timer_;
 
     DISALLOW_COPY_AND_ASSIGN(Scope);
   };