Track thread activities in order to diagnose hangs.

chrome/browser/chrome_browser_field_trials_desktop.cc

Index: chrome/browser/chrome_browser_field_trials_desktop.cc
diff --git a/chrome/browser/chrome_browser_field_trials_desktop.cc b/chrome/browser/chrome_browser_field_trials_desktop.cc
index 3970bf2f0b90b873b2ea5497cef6a28e509ec351..5a0b11be8290c1d5477a83590877be63b50e05ef 100644
--- a/chrome/browser/chrome_browser_field_trials_desktop.cc
+++ b/chrome/browser/chrome_browser_field_trials_desktop.cc
@@ -7,8 +7,11 @@
 #include <string>
 
 #include "base/command_line.h"
+#include "base/debug/activity_tracker.h"
 #include "base/metrics/field_trial.h"
+#include "base/path_service.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
+#include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/variations/variations_util.h"
 #include "components/variations/variations_associated_data.h"
@@ -52,6 +55,14 @@ void SetupDesktopFieldTrials(const base::CommandLine& parsed_command_line) {
   prerender::ConfigurePrerender(parsed_command_line);
   SetupLightSpeedTrials();
   SetupStunProbeTrial();
+
+  // Track code activities (such as posting task, blocking on locks, and

[Alexei Svitkine (slow), 2016/08/02 21:18:51]

Please move this block to a helper function, which can live in this file.

[bcwhite, 2016/08/04 14:06:20]

Done.

+  // joining threads) that can cause threads to hang.
+  base::FilePath activity_file;
+  bool success = base::PathService::Get(chrome::DIR_USER_DATA, &activity_file);
+  DCHECK(success);
+  activity_file = activity_file.AppendASCII("HangDebugInfo");
+  base::debug::SetupGlobalActivityTrackerFieldTrial(activity_file);
 }
 
 }  // namespace chrome