[tracing] StartupTracingController

Refactor startup tracing logic out of TracingControllerImpl and use
modern TracingSession from Perfetto client API directly.

This allows for much greater simplification, including removing
substantial amount of logic from TracingControllerImpl (including
logic for finishing trace recording after a timeout) and removing
PerfettoFileTracer.

This also allows for a clean implementation of features like streaming
trace to a file and merging browsertest and startup tracing logic.

R=eseckler@chromium.org,skyostil@chromium.org
BUG=1157954,1082916

Change-Id: Id4c608b05cbd6b0696cb8e3445888b6a9d86c797
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2587040
Commit-Queue: Alexander Timin <altimin@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Eric Seckler <eseckler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839190}

components/tracing/common/trace_startup_config.cc

@@ -83,7 +83,7 @@ TraceStartupConfig::TraceStartupConfig() {
   if (EnableFromCommandLine()) {
     DCHECK(IsEnabled());
   } else if (EnableFromConfigFile()) {
-    DCHECK(IsEnabled() || IsUsingPerfettoOutput());
+    DCHECK(IsEnabled());
   } else if (EnableFromBackgroundTracing()) {
     DCHECK(IsEnabled());
     DCHECK(!IsTracingStartupForDuration());
@@ -99,12 +99,7 @@ TraceStartupConfig::TraceStartupConfig() {
 TraceStartupConfig::~TraceStartupConfig() = default;
 
 bool TraceStartupConfig::IsEnabled() const {
-  // TODO(oysteine): Support early startup tracing using Perfetto
-  // output; right now the early startup tracing gets controlled
-  // through the TracingController, and the Perfetto output is
-  // using the Consumer Mojo interface; the two can't be used
-  // together.
-  return is_enabled_ && !IsUsingPerfettoOutput();
+  return is_enabled_;
 }
 
 void TraceStartupConfig::SetDisabled() {
@@ -117,15 +112,20 @@ bool TraceStartupConfig::IsTracingStartupForDuration() const {
 }
 
 base::trace_event::TraceConfig TraceStartupConfig::GetTraceConfig() const {
-  DCHECK(IsEnabled() || IsUsingPerfettoOutput());
+  DCHECK(IsEnabled());
   return trace_config_;
 }
 
 int TraceStartupConfig::GetStartupDuration() const {
-  DCHECK(IsEnabled() || IsUsingPerfettoOutput());
+  DCHECK(IsEnabled());
   return startup_duration_in_seconds_;
 }
 
+TraceStartupConfig::OutputFormat TraceStartupConfig::GetOutputFormat() const {
+  DCHECK(IsEnabled());
+  return output_format_;
+}
+
 bool TraceStartupConfig::ShouldTraceToResultFile() const {
   return IsEnabled() && should_trace_to_result_file_;
 }
@@ -140,11 +140,6 @@ void TraceStartupConfig::OnTraceToResultFileFinished() {
   finished_writing_to_file_ = true;
 }
 
-bool TraceStartupConfig::IsUsingPerfettoOutput() const {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kPerfettoOutputFile);
-}
-
 void TraceStartupConfig::SetBackgroundStartupTracingEnabled(bool enabled) {
 #if defined(OS_ANDROID)
   base::android::SetBackgroundStartupTracingFlag(enabled);
@@ -168,7 +163,6 @@ bool TraceStartupConfig::AttemptAdoptBySessionOwner(SessionOwner owner) {
 bool TraceStartupConfig::EnableFromCommandLine() {
   auto* command_line = base::CommandLine::ForCurrentProcess();
 
-  // Startup duration can be used by along with perfetto-output-file flag.
   if (command_line->HasSwitch(switches::kTraceStartupDuration)) {
     std::string startup_duration_str =
         command_line->GetSwitchValueASCII(switches::kTraceStartupDuration);
@@ -180,6 +174,12 @@ bool TraceStartupConfig::EnableFromCommandLine() {
     }
   }
 
+  if (command_line->GetSwitchValueASCII(switches::kTraceStartupFormat) ==
+      "proto") {
+    // Default is "json".
+    output_format_ = OutputFormat::kProto;
+  }
+
   if (!command_line->HasSwitch(switches::kTraceStartup))
     return false;
 

components/tracing/common/trace_startup_config.h

@@ -94,6 +94,11 @@ class TRACING_EXPORT TraceStartupConfig {
     kSystemTracing
   };
 
+  enum class OutputFormat {
+    kLegacyJSON,
+    kProto,
+  };
+
   static TraceStartupConfig* GetInstance();
 
   // Default minimum startup trace config with enough events to debug issues.
@@ -135,6 +140,8 @@ class TRACING_EXPORT TraceStartupConfig {
 
   SessionOwner GetSessionOwner() const;
 
+  OutputFormat GetOutputFormat() const;
+
   // Called by a potential session owner to determine if it should take
   // ownership of the startup tracing session and begin tracing. Returns |true|
   // if the passed |owner| should adopt the session.
@@ -152,8 +159,6 @@ class TRACING_EXPORT TraceStartupConfig {
   TraceStartupConfig();
   ~TraceStartupConfig();
 
-  bool IsUsingPerfettoOutput() const;
-
   bool EnableFromCommandLine();
   bool EnableFromConfigFile();
   bool EnableFromBackgroundTracing();
@@ -170,6 +175,7 @@ class TRACING_EXPORT TraceStartupConfig {
   bool finished_writing_to_file_ = false;
   SessionOwner session_owner_ = SessionOwner::kTracingController;
   bool session_adopted_ = false;
+  OutputFormat output_format_ = OutputFormat::kLegacyJSON;
 
   DISALLOW_COPY_AND_ASSIGN(TraceStartupConfig);
 };

components/tracing/common/tracing_switches.cc

@@ -37,6 +37,14 @@ const char kTraceStartupDuration[]          = "trace-startup-duration";
 // all events since startup.
 const char kTraceStartupFile[]              = "trace-startup-file";
 
+// Sets the output format for the trace, valid values are "json" and "proto".
+// If not set, the current default is "json".
+// "proto", unlike json, supports writing the trace into the output file
+// incrementally and is more likely to retain more data if the browser process
+// unexpectedly terminates.
+// Ignored if "trace-startup-owner" is not "controller".
+const char kTraceStartupFormat[] = "trace-startup-format";
+
 // If supplied, sets the tracing record mode and options; otherwise, the default
 // "record-until-full" mode will be used.
 const char kTraceStartupRecordMode[] = "trace-startup-record-mode";
@@ -66,13 +74,6 @@ const char kTraceStartupEnablePrivacyFiltering[] =
 // Repeat internable data for each TraceEvent in the perfetto proto format.
 const char kPerfettoDisableInterning[] = "perfetto-disable-interning";
 
-// If supplied, will enable Perfetto startup tracing and stream the
-// output to the given file. On Android, if no file is provided, automatically
-// generate a file to write the output to.
-// TODO(oysteine): Remove once Perfetto starts early enough after
-// process startup to be able to replace the legacy startup tracing.
-const char kPerfettoOutputFile[] = "perfetto-output-file";
-
 // Sends a pretty-printed version of tracing info to the console.
 const char kTraceToConsole[]                = "trace-to-console";
 

components/tracing/common/tracing_switches.h

@@ -15,10 +15,10 @@ TRACING_EXPORT extern const char kTraceStartup[];
 TRACING_EXPORT extern const char kTraceStartupDuration[];
 TRACING_EXPORT extern const char kTraceStartupFile[];
 TRACING_EXPORT extern const char kTraceStartupRecordMode[];
+TRACING_EXPORT extern const char kTraceStartupFormat[];
 TRACING_EXPORT extern const char kTraceStartupOwner[];
 TRACING_EXPORT extern const char kTraceStartupEnablePrivacyFiltering[];
 TRACING_EXPORT extern const char kPerfettoDisableInterning[];
-TRACING_EXPORT extern const char kPerfettoOutputFile[];
 TRACING_EXPORT extern const char kTraceToConsole[];
 TRACING_EXPORT extern const char kTraceUploadURL[];
 

content/browser/BUILD.gn

@@ -1742,8 +1742,8 @@ source_set("browser") {
     "tracing/file_tracing_provider_impl.h",
     "tracing/memory_instrumentation_util.cc",
     "tracing/memory_instrumentation_util.h",
-    "tracing/perfetto_file_tracer.cc",
-    "tracing/perfetto_file_tracer.h",
+    "tracing/startup_tracing_controller.cc",
+    "tracing/startup_tracing_controller.h",
     "tracing/tracing_controller_impl.cc",
     "tracing/tracing_controller_impl.h",
     "tracing/tracing_controller_impl_data_endpoint.cc",

content/browser/browser_main_loop.cc

@@ -56,7 +56,6 @@
 #include "components/discardable_memory/service/discardable_shared_memory_manager.h"
 #include "components/services/storage/dom_storage/storage_area_impl.h"
 #include "components/tracing/common/trace_startup_config.h"
-#include "components/tracing/common/trace_to_console.h"
 #include "components/tracing/common/tracing_switches.h"
 #include "components/viz/host/compositing_mode_reporter_impl.h"
 #include "components/viz/host/gpu_host_impl.h"
@@ -90,6 +89,7 @@
 #include "content/browser/startup_data_impl.h"
 #include "content/browser/startup_task_runner.h"
 #include "content/browser/tracing/background_tracing_manager_impl.h"
+#include "content/browser/tracing/startup_tracing_controller.h"
 #include "content/browser/tracing/tracing_controller_impl.h"
 #include "content/browser/utility_process_host.h"
 #include "content/browser/webrtc/webrtc_internals.h"
@@ -1427,7 +1427,7 @@ void BrowserMainLoop::InitializeMojo() {
   // need to start tracing for all other tracing agents, which require threads.
   // We can only do this after starting the main message loop to avoid calling
   // MessagePumpForUI::ScheduleWork() before MessagePumpForUI::Start().
-  TracingControllerImpl::GetInstance()->StartStartupTracingIfNeeded();
+  StartupTracingController::GetInstance().StartIfNeeded();
 
 #if BUILDFLAG(MOJO_RANDOM_DELAYS_ENABLED)
   mojo::BeginRandomMojoDelays();

content/browser/browser_main_runner_impl.cc

@@ -21,7 +21,7 @@
 #include "components/tracing/common/tracing_switches.h"
 #include "content/browser/browser_main_loop.h"
 #include "content/browser/notification_service_impl.h"
-#include "content/browser/tracing/tracing_controller_impl.h"
+#include "content/browser/tracing/startup_tracing_controller.h"
 #include "content/common/content_switches_internal.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
@@ -167,8 +167,7 @@ void BrowserMainRunnerImpl::Shutdown() {
   main_loop_->PreShutdown();
 
   // Finalize the startup tracing session if it is still active.
-  if (TracingControllerImpl::GetInstance())
-    TracingControllerImpl::GetInstance()->FinalizeStartupTracingIfNeeded();
+  StartupTracingController::GetInstance().WaitUntilStopped();
 
   {
     // The trace event has to stay between profiler creation and destruction.

content/browser/tracing/DEPS

@@ -12,7 +12,7 @@ specific_include_rules = {
   "cast_tracing_agent\.": [
     "+chromecast/tracing"
   ],
-  "perfetto_file_tracer\.cc": [
+  "startup_tracing_controller\.cc": [
     "+third_party/perfetto"
   ]
 }