Ensure every process calls InitTracingAfterThreadPoolStart.

This adds a global CHECK that ensures we hopefully won't miss new processes as
they are added.

This enables all processes to initialize system tracing as early as possible.

Bug: 979576
Change-Id: Id9d841dad5980cf82e46586238fe682722558cea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1748886
Commit-Queue: Stephen Nusko <nuskos@chromium.org>
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Eric Seckler <eseckler@chromium.org>
Auto-Submit: Stephen Nusko <nuskos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686469}

content/app/content_main_runner_impl.cc

@@ -909,10 +909,10 @@ int ContentMainRunnerImpl::RunServiceManager(MainFunctionParams& main_params,
       StartBrowserThreadPool();
     }
 
-    tracing::InitTracingPostThreadPoolStart();
-
     BrowserTaskExecutor::PostFeatureListSetup();
 
+    tracing::InitTracingPostThreadPoolStartAndFeatureList();
+
     delegate_->PostTaskSchedulerStart();
 
     if (should_start_service_manager_only)

content/child/child_process.cc

@@ -16,6 +16,7 @@
 #include "base/threading/thread_local.h"
 #include "build/build_config.h"
 #include "content/child/child_thread_impl.h"
+#include "services/tracing/public/cpp/trace_startup.h"
 #include "third_party/blink/public/common/features.h"
 
 namespace content {
@@ -51,6 +52,7 @@ ChildProcess::ChildProcess(base::ThreadPriority io_thread_priority,
     DCHECK(base::ThreadPoolInstance::Get());
     initialized_thread_pool_ = true;
   }
+  tracing::InitTracingPostThreadPoolStartAndFeatureList();
 
   // We can't recover from failing to start the IO thread.
   base::Thread::Options thread_options(base::MessagePumpType::IO, 0);

content/public/test/DEPS

@@ -11,6 +11,7 @@ include_rules = [
   "+services/audio/public/mojom",
   "+services/network",
   "+services/service_manager",
+  "+services/tracing/public/cpp",
   "+testing/android/native_test/native_browser_test_support.h",
   "+ui/ozone/public",
   "+ui/views/test",

content/public/test/browser_test_base.cc

@@ -62,6 +62,7 @@
 #include "services/network/public/mojom/network_service_test.mojom.h"
 #include "services/service_manager/embedder/switches.h"
 #include "services/service_manager/public/cpp/connector.h"
+#include "services/tracing/public/cpp/trace_startup.h"
 #include "ui/base/platform_window_defaults.h"
 #include "ui/compositor/compositor_switches.h"
 #include "ui/display/display_switches.h"
@@ -412,6 +413,7 @@ void BrowserTestBase::SetUp() {
 
     StartBrowserThreadPool();
     BrowserTaskExecutor::PostFeatureListSetup();
+    tracing::InitTracingPostThreadPoolStartAndFeatureList();
     delegate->PostTaskSchedulerStart();
   }
 

services/tracing/public/cpp/perfetto/perfetto_traced_process.cc

@@ -12,6 +12,7 @@
 #include "build/build_config.h"
 #include "services/tracing/public/cpp/perfetto/dummy_producer.h"
 #include "services/tracing/public/cpp/perfetto/producer_client.h"
+#include "services/tracing/public/cpp/trace_startup.h"
 #include "services/tracing/public/cpp/tracing_features.h"
 
 #if defined(OS_ANDROID)
@@ -79,6 +80,7 @@ PerfettoTracedProcess::PerfettoTracedProcess()
 
 PerfettoTracedProcess::PerfettoTracedProcess(const char* system_socket)
     : producer_client_(std::make_unique<ProducerClient>(GetTaskRunner())) {
+  CHECK(IsTracingInitialized());
   DETACH_FROM_SEQUENCE(sequence_checker_);
   // All communication with the system Perfetto service should occur on a single
   // sequence. To ensure we set up the socket correctly we construct the
@@ -143,6 +145,7 @@ PerfettoTaskRunner* PerfettoTracedProcess::GetTaskRunner() {
 void PerfettoTracedProcess::ResetTaskRunnerForTesting(
     scoped_refptr<base::SequencedTaskRunner> task_runner) {
   GetTaskRunner()->ResetTaskRunnerForTesting(task_runner);
+  InitTracingPostThreadPoolStartAndFeatureList();
   // Detaching the sequence_checker_ must happen after we reset the task runner.
   // This is because the Get() could call the constructor (if this is the first
   // call to Get()) which would then PostTask which would create races if we

services/tracing/public/cpp/perfetto/trace_event_data_source.cc

@@ -33,6 +33,7 @@
 #include "services/tracing/public/cpp/perfetto/traced_value_proto_writer.h"
 #include "services/tracing/public/cpp/perfetto/track_event_thread_local_event_sink.h"
 #include "services/tracing/public/cpp/trace_event_args_whitelist.h"
+#include "services/tracing/public/cpp/trace_startup.h"
 #include "services/tracing/public/mojom/constants.mojom.h"
 #include "third_party/perfetto/include/perfetto/ext/tracing/core/shared_memory_arbiter.h"
 #include "third_party/perfetto/include/perfetto/ext/tracing/core/startup_trace_writer.h"
@@ -287,6 +288,7 @@ void TraceEventDataSource::SetupStartupTracing(bool privacy_filtering_enabled) {
 }
 
 void TraceEventDataSource::OnTaskSchedulerAvailable() {
+  CHECK(IsTracingInitialized());
   {
     base::AutoLock lock(lock_);
     if (!startup_writer_registry_)

services/tracing/public/cpp/trace_startup.cc

@@ -6,6 +6,7 @@
 
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/task/thread_pool/thread_pool.h"
 #include "base/trace_event/trace_log.h"
 #include "components/tracing/common/trace_startup_config.h"
 #include "components/tracing/common/trace_to_console.h"
@@ -15,12 +16,17 @@
 #include "services/tracing/public/cpp/tracing_features.h"
 
 namespace tracing {
-
 namespace {
 using base::trace_event::TraceConfig;
 using base::trace_event::TraceLog;
 }  // namespace
 
+bool g_tracing_initialized_after_threadpool_and_featurelist = false;
+
+bool IsTracingInitialized() {
+  return g_tracing_initialized_after_threadpool_and_featurelist;
+}
+
 void EnableStartupTracingIfNeeded() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
@@ -66,7 +72,17 @@ void EnableStartupTracingIfNeeded() {
   }
 }
 
-void InitTracingPostThreadPoolStart() {
+void InitTracingPostThreadPoolStartAndFeatureList() {
+  if (g_tracing_initialized_after_threadpool_and_featurelist) {
+    return;
+  }
+  g_tracing_initialized_after_threadpool_and_featurelist = true;
+  // TODO(nuskos): We should switch these to DCHECK once we're reasonably
+  // confident we've ensured this is called properly in all processes. Probably
+  // after M78 release has been cut (since we'll verify in the rollout of M78).
+  CHECK(base::ThreadPoolInstance::Get());
+  CHECK(base::FeatureList::GetInstance());
+  // Below are the things tracing must do once per process.
   TraceEventDataSource::GetInstance()->OnTaskSchedulerAvailable();
   if (base::FeatureList::IsEnabled(features::kEnablePerfettoSystemTracing)) {
     // To ensure System tracing connects we have to initialize the process wide

services/tracing/public/cpp/trace_startup.h

@@ -9,14 +9,19 @@
 
 namespace tracing {
 
-// If startup tracing command line flags are specified for the process, enables
+// Returns true if InitTracingPostThreadPoolStartAndFeatureList has been called
+// for this process.
+bool COMPONENT_EXPORT(TRACING_CPP) IsTracingInitialized();
+
 // TraceLog with config based on the command line flags. Also hooks up service
 // callbacks in TraceLog if necessary. The latter is required when the perfetto
 // tracing backend is used.
 void COMPONENT_EXPORT(TRACING_CPP) EnableStartupTracingIfNeeded();
 
-// Initialize tracing components that require task runners.
-void COMPONENT_EXPORT(TRACING_CPP) InitTracingPostThreadPoolStart();
+// Initialize tracing components that require task runners. Will switch
+// IsTracingInitialized() to return true.
+void COMPONENT_EXPORT(TRACING_CPP)
+    InitTracingPostThreadPoolStartAndFeatureList();
 
 }  // namespace tracing