DevTools: Do not create TracingCpuProfiler instance.

It is created automatically by V8 since version 6.8.

Change-Id: Ib32dc5dcc356d5b8f3b0e4ddf9785eff409d67df
Reviewed-on: https://chromium-review.googlesource.com/1015604
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551561}

third_party/blink/renderer/core/inspector/thread_debugger.cc

@@ -34,8 +34,7 @@ namespace blink {
 
 ThreadDebugger::ThreadDebugger(v8::Isolate* isolate)
     : isolate_(isolate),
-      v8_inspector_(v8_inspector::V8Inspector::create(isolate, this)),
-      v8_tracing_cpu_profiler_(v8::TracingCpuProfiler::Create(isolate)) {}
+      v8_inspector_(v8_inspector::V8Inspector::create(isolate, this)) {}
 
 ThreadDebugger::~ThreadDebugger() = default;
 

third_party/blink/renderer/core/inspector/thread_debugger.h

@@ -15,7 +15,6 @@
 #include "third_party/blink/renderer/platform/wtf/forward.h"
 #include "third_party/blink/renderer/platform/wtf/vector.h"
 #include "v8/include/v8-inspector.h"
-#include "v8/include/v8-profiler.h"
 #include "v8/include/v8.h"
 
 namespace blink {
@@ -110,7 +109,6 @@ class CORE_EXPORT ThreadDebugger : public v8_inspector::V8InspectorClient,
       const v8::FunctionCallbackInfo<v8::Value>&);
 
   std::unique_ptr<v8_inspector::V8Inspector> v8_inspector_;
-  std::unique_ptr<v8::TracingCpuProfiler> v8_tracing_cpu_profiler_;
   Vector<std::unique_ptr<TaskRunnerTimer<ThreadDebugger>>> timers_;
   Vector<v8_inspector::V8InspectorClient::TimerCallback> timer_callbacks_;
   Vector<void*> timer_data_;