Remove some unneeded profiling flags (#4827)

content_handler/app.cc

@@ -66,7 +66,6 @@ App::App() {
 
   blink::Settings settings;
   settings.enable_observatory = true;
-  settings.enable_dart_profiling = true;
   blink::Settings::Set(settings);
 
   fonts::FontProviderPtr font_provider(

runtime/dart_init.cc

@@ -508,10 +508,6 @@ static std::vector<const char*> ProfilingFlags(bool enable_profiling) {
   // flags.
   if (enable_profiling) {
     return {
-        // Dart assumes ARM devices are insufficiently powerful and sets the
-        // default profile period to 100Hz. This number is suitable for older
-        // Raspberry Pi devices but quite low for current smartphones.
-        "--profile_period=1000",
         // This is the default. But just be explicit.
         "--profiler",
         // This instructs the profiler to walk C++ frames, and to include