Removed unneeded metadata fields from trace log

This removes process_name and thread_name from trace log, these fields
are now recorded in perfetto, so it's not necessary to record them
client side.

Change-Id: I6591c25d572cd97b54d024ffcb3dcc00597d63fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2640819Reviewed-by: ssid <ssid@chromium.org>
Commit-Queue: Salvador Guerrero <salg@google.com>
Cr-Commit-Position: refs/heads/master@{#846445}

base/trace_event/trace_event_unittest.cc

@@ -1686,43 +1686,6 @@ TEST_F(TraceEventTestFixture, ThreadNames) {
   }
 }
 
-TEST_F(TraceEventTestFixture, ThreadNameChanges) {
-  BeginTrace();
-
-  PlatformThread::SetName("");
-  TRACE_EVENT_INSTANT0("drink", "water", TRACE_EVENT_SCOPE_THREAD);
-
-  PlatformThread::SetName("cafe");
-  TRACE_EVENT_INSTANT0("drink", "coffee", TRACE_EVENT_SCOPE_THREAD);
-
-  PlatformThread::SetName("shop");
-  // No event here, so won't appear in combined name.
-
-  PlatformThread::SetName("pub");
-  TRACE_EVENT_INSTANT0("drink", "beer", TRACE_EVENT_SCOPE_THREAD);
-  TRACE_EVENT_INSTANT0("drink", "wine", TRACE_EVENT_SCOPE_THREAD);
-
-  PlatformThread::SetName(" bar");
-  TRACE_EVENT_INSTANT0("drink", "whisky", TRACE_EVENT_SCOPE_THREAD);
-
-  EndTraceAndFlush();
-
-  std::vector<const DictionaryValue*> items =
-      FindTraceEntries(trace_parsed_, "thread_name");
-  EXPECT_EQ(1u, items.size());
-  ASSERT_GT(items.size(), 0u);
-  const DictionaryValue* item = items[0];
-  ASSERT_TRUE(item);
-  int tid;
-  EXPECT_TRUE(item->GetInteger("tid", &tid));
-  EXPECT_EQ(PlatformThread::CurrentId(), static_cast<PlatformThreadId>(tid));
-
-  std::string expected_name = "cafe,pub, bar";
-  std::string tmp;
-  EXPECT_TRUE(item->GetString("args.name", &tmp));
-  EXPECT_EQ(expected_name, tmp);
-}
-
 // Test that the disabled trace categories are included/excluded from the
 // trace output correctly.
 TEST_F(TraceEventTestFixture, DisabledCategories) {

base/trace_event/trace_log.cc

@@ -1579,11 +1579,6 @@ void TraceLog::AddMetadataEventsWhileLocked() {
                                 "sort_index", process_sort_index_);
   }
 
-  if (!process_name_.empty()) {
-    AddMetadataEventWhileLocked(current_thread_id, "process_name", "name",
-                                process_name_);
-  }
-
   TimeDelta process_uptime = TRACE_TIME_NOW() - process_creation_time_;
   AddMetadataEventWhileLocked(current_thread_id, "process_uptime_seconds",
                               "uptime", process_uptime.InSeconds());
@@ -1617,16 +1612,6 @@ void TraceLog::AddMetadataEventsWhileLocked() {
                                 it.second);
   }
 
-  // TODO(ssid): Stop emitting and tracking thread names when perfetto is
-  // enabled and after crbug/978093 if fixed. The JSON exporter will emit thread
-  // names from thread descriptors.
-  AutoLock thread_info_lock(thread_info_lock_);
-  for (const auto& it : thread_names_) {
-    if (it.second.empty())
-      continue;
-    AddMetadataEventWhileLocked(it.first, "thread_name", "name", it.second);
-  }
-
   // If buffer is full, add a metadata record to report this.
   if (!buffer_limit_reached_timestamp_.is_null()) {
     AddMetadataEventWhileLocked(current_thread_id, "trace_buffer_overflowed",

services/tracing/public/cpp/trace_event_args_allowlist.cc

@@ -50,6 +50,7 @@ const char* const kMemoryPressureEventsAllowedArgs[] = {
     "level", "listener_creation_info", nullptr};
 
 const AllowlistEntry kEventArgsAllowlist[] = {
+    // Thread and process names are now recorded in perfetto.
     {"__metadata", "thread_name", nullptr},
     {"__metadata", "process_name", nullptr},
     {"__metadata", "process_uptime_seconds", nullptr},