Move trace events for CPU sampling to a debug

The CPU sampling profiler trace events were added on windows to
investigate some strange patterns happening in the field. We have enough
data to make some analysis over it.

There are plan to add sampling profiler to renderers, io-thread and so on.
This will increase the amount of trace events in a trace and it's better
to avoid producing events that are not needed.

We are moving these trace events to a debug category. This will allow us
to make a specific slow-reports scenario if we still want to analyze the
sampling profiler and it's behavior.

R=wittman@chromium.org

Change-Id: If348399336e60c4aa511ea783aec4c92d0575462
Reviewed-on: https://chromium-review.googlesource.com/c/1340908Reviewed-by: oysteine <oysteine@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609404}

base/profiler/native_stack_sampler_win.cc

@@ -355,7 +355,8 @@ NativeStackSamplerError SuspendThreadAndRecordStack(
   uintptr_t bottom = 0u;
 
   {
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"), "SuspendThread");
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler.debug"),
+                 "SuspendThread");
     {
       ScopedSuspendThread suspend_thread(thread_handle);
 
@@ -393,7 +394,8 @@ NativeStackSamplerError SuspendThreadAndRecordStack(
     test_delegate->OnPreStackWalk();
 
   {
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"), "RecordStack");
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler.debug"),
+                 "RecordStack");
 
     RewritePointersToStackMemory(top, bottom, &thread_context,
                                  stack_copy_buffer);
@@ -452,7 +454,7 @@ void NativeStackSamplerWin::ProfileRecordingStarting() {
 std::vector<Frame> NativeStackSamplerWin::RecordStackFrames(
     StackBuffer* stack_buffer,
     ProfileBuilder* profile_builder) {
-  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"),
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler.debug"),
                "NativeStackSamplerWin::RecordStackFrames");
   DCHECK(stack_buffer);
 
@@ -476,7 +478,7 @@ std::vector<Frame> NativeStackSamplerWin::RecordStackFrames(
 
 std::vector<Frame> NativeStackSamplerWin::CreateFrames(
     const std::vector<RecordedFrame>& stack) {
-  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"),
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler.debug"),
                "NativeStackSamplerWin::CreateFrames");
 
   std::vector<Frame> frames;

base/trace_event/builtin_categories.h

@@ -161,6 +161,7 @@
   X(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler.frames"))              \
   X(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler.now"))                 \
   X(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"))                           \
+  X(TRACE_DISABLED_BY_DEFAULT("cpu_profiler.debug"))                     \
   X(TRACE_DISABLED_BY_DEFAULT("devtools.screenshot"))                    \
   X(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"))                      \
   X(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.frame"))                \