Do not modify the set of active streams within the embedder tracing c…

…allbacks (flutter#2600) Dart invokes Start/StopTracing callbacks within the _setVMTimelineFlags service method whenever the embedder timeline stream toggles on or off. Flutter's implementation of these callbacks was modifying the set of enabled streams, which could override the intended behavior of _setVMTimelineFlags. Start/StopTracing will now only control Flutter's embedder-specific log. Also needed to change the Flutter engine's --trace-startup flag to set the corresponding timeline stream flag on the Dart VM.
subashp · Apr 19, 2016 · 48de25e · 48de25e
1 parent 284929b
commit 48de25e
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Showing 5 changed files with 9 additions and 16 deletions.
diff --git a/sky/engine/core/script/dart_init.cc b/sky/engine/core/script/dart_init.cc
@@ -102,6 +102,10 @@ static const char* kDartStartPausedArgs[]{
     "--pause_isolates_on_start",
 };
 
+static const char* kDartTraceStartupArgs[]{
+    "--timeline_streams=Compiler,Dart,Embedder,GC",
+};
+
 const char kFileUriPrefix[] = "file://";
 
 const char kDartFlags[] = "dart-flags";
@@ -410,6 +414,9 @@ void InitDartVM() {
   if (SkySettings::Get().start_paused)
     args.append(kDartStartPausedArgs, arraysize(kDartStartPausedArgs));
 
+  if (SkySettings::Get().trace_startup)
+    args.append(kDartTraceStartupArgs, arraysize(kDartTraceStartupArgs));
+
   Vector<std::string> dart_flags;
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(kDartFlags)) {
     // Instruct the VM to ignore unrecognized flags.

diff --git a/sky/engine/public/platform/sky_settings.h b/sky/engine/public/platform/sky_settings.h
@@ -16,6 +16,7 @@ struct SkySettings {
   uint32_t observatory_port = 0;
   bool start_paused = false;
   bool enable_dart_checked_mode = false;
+  bool trace_startup = false;
 
   static const SkySettings& Get();
   static void Set(const SkySettings& settings);

diff --git a/sky/shell/shell.cc b/sky/shell/shell.cc
@@ -135,12 +135,10 @@ void Shell::InitStandalone(std::string icu_data_path) {
   settings.start_paused = command_line.HasSwitch(switches::kStartPaused);
   settings.enable_dart_checked_mode =
       command_line.HasSwitch(switches::kEnableCheckedMode);
+  settings.trace_startup = command_line.HasSwitch(switches::kTraceStartup);
   blink::SkySettings::Set(settings);
 
   Init();
-
-  if (command_line.HasSwitch(switches::kTraceStartup))
-    Shared().tracing_controller().StartTracing();
 }
 
 void Shell::Init() {

diff --git a/sky/shell/tracing_controller.cc b/sky/shell/tracing_controller.cc
@@ -171,16 +171,11 @@ void TracingController::StartTracing() {
 
   tracing_active_ = true;
 
-  StartDartTracing();
   StartBaseTracing();
 
   AddTraceMetadata();
 }
 
-void TracingController::StartDartTracing() {
-  Dart_GlobalTimelineSetRecordedStreams(DART_TIMELINE_STREAM_ALL);
-}
-
 void TracingController::StartBaseTracing() {
   namespace TE = base::trace_event;
   auto config = TE::TraceConfig("*", TE::RECORD_CONTINUOUSLY);
@@ -199,7 +194,6 @@ void TracingController::StopTracing() {
   tracing_active_ = false;
 
   StopBaseTracing();
-  StopDartTracing();
 }
 
 void TracingController::StopBaseTracing() {
@@ -209,10 +203,6 @@ void TracingController::StopBaseTracing() {
   log->SetEventCallbackDisabled();
 }
 
-void TracingController::StopDartTracing() {
-  Dart_GlobalTimelineSetRecordedStreams(DART_TIMELINE_STREAM_DISABLE);
-}
-
 base::FilePath TracingController::TracePathWithExtension(
     base::FilePath dir,
     std::string extension) const {

diff --git a/sky/shell/tracing_controller.h b/sky/shell/tracing_controller.h
@@ -49,9 +49,6 @@ class TracingController {
 
   void StopBaseTracing();
 
-  void StartDartTracing();
-  void StopDartTracing();
-
   base::FilePath TracePathWithExtension(base::FilePath dir,
                                         std::string extension) const;