Add sampled thread id to the stack sampling events

This CL is adding the thread id for each sampled stack event.
This will allow using multiple sampling profiler in the same process.

We are planning to sample the UI and the IO thread in the browser process.


R=ssid@chromium.org

Change-Id: Ia520c7886356fa7bf5d5f069d079125db156995d
Reviewed-on: https://chromium-review.googlesource.com/c/1310500Reviewed-by: Gabriel Charette <gab@chromium.org>
Reviewed-by: ssid <ssid@chromium.org>
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606557}

components/tracing/common/tracing_sampler_profiler.cc

@@ -36,12 +36,15 @@ std::string GetFrameNameFromOffsetAddr(uintptr_t offset_from_module_base) {
 class TracingProfileBuilder
     : public base::StackSamplingProfiler::ProfileBuilder {
  public:
+  TracingProfileBuilder(base::PlatformThreadId sampled_thread_id)
+      : sampled_thread_id_(sampled_thread_id) {}
+
   void OnSampleCompleted(
       std::vector<base::StackSamplingProfiler::Frame> frames) override {
     if (frames.empty()) {
-      TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"),
+      TRACE_EVENT_INSTANT2(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"),
                            "StackCpuSampling", TRACE_EVENT_SCOPE_THREAD,
-                           "frames", "empty");
+                           "frames", "empty", "thread_id", sampled_thread_id_);
 
       return;
     }
@@ -101,13 +104,16 @@ class TracingProfileBuilder
                           module_name.c_str(), frame.module.id.c_str());
     }
 
-    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"),
+    TRACE_EVENT_INSTANT2(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"),
                          "StackCpuSampling", TRACE_EVENT_SCOPE_THREAD, "frames",
-                         result);
+                         result, "thread_id", sampled_thread_id_);
   }
 
   void OnProfileCompleted(base::TimeDelta profile_duration,
                           base::TimeDelta sampling_period) override {}
+
+ private:
+  base::PlatformThreadId sampled_thread_id_;
 };
 
 }  // namespace
@@ -153,11 +159,13 @@ void TracingSamplerProfiler::OnTraceLogEnabled() {
 #if defined(OS_ANDROID) && BUILDFLAG(CAN_UNWIND_WITH_CFI_TABLE) && \
     defined(OFFICIAL_BUILD)
   profiler_ = std::make_unique<base::StackSamplingProfiler>(
-      sampled_thread_id_, params, std::make_unique<TracingProfileBuilder>(),
+      sampled_thread_id_, params,
+      std::make_unique<TracingProfileBuilder>(sampled_thread_id_),
       std::make_unique<NativeStackSamplerAndroid>(sampled_thread_id_));
 #else
   profiler_ = std::make_unique<base::StackSamplingProfiler>(
-      sampled_thread_id_, params, std::make_unique<TracingProfileBuilder>());
+      sampled_thread_id_, params,
+      std::make_unique<TracingProfileBuilder>(sampled_thread_id_));
 #endif
   profiler_->Start();
 }