chrome: Move ThreadProfiler initialization to the UI thread (fixes #3465)

ThreadProfiler::CreateAndStartOnMainThread and SetMainThreadTaskRunnerImpl
should be called on the same thread.

libcef/browser/main_runner.cc

@@ -394,6 +394,7 @@ bool CefMainRunner::ContentMainRun(bool* initialized,
 
     if (!CreateUIThread(base::BindOnce(
             [](CefMainRunner* runner, base::WaitableEvent* event) {
+              runner->main_delegate_->BeforeUIThreadInitialize();
               content::ContentMainRun(runner->main_runner_.get());
               event->Signal();
             },
@@ -408,6 +409,7 @@ bool CefMainRunner::ContentMainRun(bool* initialized,
     uithread_startup_event.Wait();
   } else {
     *initialized = true;
+    main_delegate_->BeforeUIThreadInitialize();
     content::ContentMainRun(main_runner_.get());
   }
 

libcef/common/chrome/chrome_main_runner_delegate.cc

@@ -40,8 +40,6 @@ void ChromeMainRunnerDelegate::BeforeMainThreadInitialize(
 #else
   base::CommandLine::Init(args.argc, args.argv);
 #endif
-
-  sampling_profiler_ = std::make_unique<MainThreadStackSamplingProfiler>();
 }
 
 void ChromeMainRunnerDelegate::BeforeMainMessageLoopRun(
@@ -70,14 +68,16 @@ bool ChromeMainRunnerDelegate::HandleMainMessageLoopQuit() {
   return true;
 }
 
+void ChromeMainRunnerDelegate::BeforeUIThreadInitialize() {
+  sampling_profiler_ = std::make_unique<MainThreadStackSamplingProfiler>();
+}
+
 void ChromeMainRunnerDelegate::AfterUIThreadShutdown() {
   static_cast<ChromeContentBrowserClient*>(
       CefAppManager::Get()->GetContentClient()->browser())
       ->CleanupOnUIThread();
   main_delegate_->CleanupOnUIThread();
-}
 
-void ChromeMainRunnerDelegate::AfterMainThreadShutdown() {
   sampling_profiler_.reset();
 }
 

libcef/common/chrome/chrome_main_runner_delegate.h

@@ -35,8 +35,8 @@ class ChromeMainRunnerDelegate : public CefMainRunnerDelegate {
   void BeforeMainThreadInitialize(const CefMainArgs& args) override;
   void BeforeMainMessageLoopRun(base::RunLoop* run_loop) override;
   bool HandleMainMessageLoopQuit() override;
+  void BeforeUIThreadInitialize() override;
   void AfterUIThreadShutdown() override;
-  void AfterMainThreadShutdown() override;
   void BeforeExecuteProcess(const CefMainArgs& args) override;
   void AfterExecuteProcess() override;
 

libcef/common/main_runner_delegate.h

@@ -24,6 +24,7 @@ class CefMainRunnerDelegate {
   virtual void BeforeMainThreadRun() {}
   virtual void BeforeMainMessageLoopRun(base::RunLoop* run_loop) {}
   virtual bool HandleMainMessageLoopQuit() { return false; }
+  virtual void BeforeUIThreadInitialize() {}
   virtual void AfterUIThreadInitialize() {}
   virtual void AfterUIThreadShutdown() {}
   virtual void BeforeMainThreadShutdown() {}