Make stack sampling profiler sample beyond startup.

chrome/browser/chrome_browser_main.h

Index: chrome/browser/chrome_browser_main.h
diff --git a/chrome/browser/chrome_browser_main.h b/chrome/browser/chrome_browser_main.h
index b00bac91570e99a78e1149a141f3d2552c617b9b..633fdcee1110365b490d62f1e606f821f515841e 100644
--- a/chrome/browser/chrome_browser_main.h
+++ b/chrome/browser/chrome_browser_main.h
@@ -19,6 +19,7 @@
 #include "chrome/browser/process_singleton.h"
 #include "chrome/browser/ui/startup/startup_browser_creator.h"
 #include "chrome/common/stack_sampling_configuration.h"
+#include "components/metrics/call_stack_profile_params.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/common/main_function_params.h"
 
@@ -153,6 +154,10 @@ class ChromeBrowserMainParts : public content::BrowserMainParts {
   // Parts are deleted in the inverse order they are added.
   std::vector<ChromeBrowserMainExtraParts*> chrome_extra_parts_;
 
+  // Parameters for |sampling_profiler_|. Not const since these may be changed
+  // when transitioning from start-up profiling to periodic profiling.
+  metrics::CallStackProfileParams sampling_profiler_params_;
+
   // A profiler that periodically samples stack traces. Used to sample startup
   // behavior.
   base::StackSamplingProfiler sampling_profiler_;