Remove scheduler tracing category

We decided to remove the scheduling category.

If we plan to look again on our the scheduler is performing through
slow-reports, we gonna add a specific scenario since this is doubling
the amoung of events.

R=oysteine@chromium.org

Change-Id: Id280597bcb41fd1a0765773c4ed42a97dabd83aa
Reviewed-on: https://chromium-review.googlesource.com/c/1307893Reviewed-by: oysteine <oysteine@chromium.org>
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604683}

content/browser/tracing/background_tracing_manager_impl.cc

@@ -675,7 +675,7 @@ TraceConfig BackgroundTracingManagerImpl::GetConfigForCategoryPreset(
     case BackgroundTracingConfigImpl::CategoryPreset::BENCHMARK_NAVIGATION: {
       auto config = TraceConfig(
           "benchmark,toplevel,ipc,base,browser,navigation,omnibox,ui,shutdown,"
-          "safe_browsing,task_scheduler,"
+          "safe_browsing,"
           "disabled-by-default-system_stats,disabled-by-default-cpu_profiler",
           record_mode);
       // Filter only browser process events.
@@ -686,8 +686,7 @@ TraceConfig BackgroundTracingManagerImpl::GetConfigForCategoryPreset(
     }
     case BackgroundTracingConfigImpl::CategoryPreset::BENCHMARK_RENDERERS:
       return TraceConfig(
-          "benchmark,toplevel,ipc,base,ui,v8,task_scheduler,renderer,blink,"
-          "blink_gc,"
+          "benchmark,toplevel,ipc,base,ui,v8,renderer,blink,blink_gc,"
           "disabled-by-default-v8.gc,"
           "disabled-by-default-blink_gc,"
           "disabled-by-default-renderer.scheduler,"