Temporary commit to evaluate perf impact of prototype CPU profiler

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 998c36218d2d464397af86505576ba5a441f542a..bc07053bf10a4fa31ca65facf07b03baa2bd7548 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -24,6 +24,7 @@
 #include "base/prefs/pref_value_store.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/process/process_info.h"
+#include "base/profiler/cpu_profiler.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
@@ -996,6 +997,9 @@ int ChromeBrowserMainParts::PreCreateThreadsImpl() {
   // IOThread's initialization which happens in BrowserProcess:PreCreateThreads.
   SetupMetricsAndFieldTrials();
 
+  std::map<std::string, std::string> params;
+  base::CpuProfiler::Initialize(params);
+
   // ChromeOS needs ResourceBundle::InitSharedInstance to be called before this.
   browser_process_->PreCreateThreads();
 
@@ -1650,6 +1654,8 @@ void ChromeBrowserMainParts::PostMainMessageLoopRun() {
   NOTREACHED();
 #else
 
+  base::CpuProfiler::Stop();
+
   // Start watching for jank during shutdown. It gets disarmed when
   // |shutdown_watcher_| object is destructed.
   metrics::MetricsService::SetExecutionPhase(