Make stack sampling profiler sample beyond startup.

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 79321911137b1aed54eb25bf6475ddc0e01cced5..a731af075cdeadc7767943a58129fe2171f469e9 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -630,16 +630,17 @@ ChromeBrowserMainParts::ChromeBrowserMainParts(
       result_code_(content::RESULT_CODE_NORMAL_EXIT),
       startup_watcher_(new StartupTimeBomb()),
       shutdown_watcher_(new ShutdownWatcherHelper()),
+      sampling_profiler_params_(
+          metrics::CallStackProfileParams::BROWSER_PROCESS,
+          metrics::CallStackProfileParams::UI_THREAD,
+          metrics::CallStackProfileParams::PROCESS_STARTUP,
+          metrics::CallStackProfileParams::MAY_SHUFFLE),
       sampling_profiler_(
           base::PlatformThread::CurrentId(),
-          StackSamplingConfiguration::Get()->
-              GetSamplingParamsForCurrentProcess(),
+          StackSamplingConfiguration::Get()
+              ->GetSamplingParamsForCurrentProcess(),
           metrics::CallStackProfileMetricsProvider::GetProfilerCallback(
-              metrics::CallStackProfileParams(
-                  metrics::CallStackProfileParams::BROWSER_PROCESS,
-                  metrics::CallStackProfileParams::UI_THREAD,
-                  metrics::CallStackProfileParams::PROCESS_STARTUP,
-                  metrics::CallStackProfileParams::MAY_SHUFFLE))),
+              &sampling_profiler_params_)),

[sky, 2017/07/12 21:42:58]

It's rather error prone to have callers be responsible for keeping around
parameters used to create an object. Can't GetProfilerCallback copy (or move)
the params?

[Alexei Svitkine (slow), 2017/07/13 17:58:22]

Done.

       profile_(NULL),
       run_message_loop_(true),
       local_state_(NULL) {