Parse startup duration flag even if trace-startup isn't set

The flag could be used along with perfetto-output-file flag.

Change-Id: Idd1c7069a0e2e29b3c33d60da02434c8b01af1ad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1774039
Commit-Queue: ssid <ssid@chromium.org>
Reviewed-by: oysteine <oysteine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691772}

components/tracing/common/trace_startup_config.cc

@@ -29,7 +29,6 @@ namespace {
 
 // Maximum trace config file size that will be loaded, in bytes.
 const size_t kTraceConfigFileSizeLimit = 64 * 1024;
-const int kDefaultStartupDuration = 5;
 
 // Trace config file path:
 // - Android: /data/local/chrome-trace-config.json
@@ -118,7 +117,7 @@ void TraceStartupConfig::SetDisabled() {
 }
 
 bool TraceStartupConfig::IsTracingStartupForDuration() const {
-  return IsEnabled() && startup_duration_ > 0 &&
+  return IsEnabled() && startup_duration_in_seconds_ > 0 &&
          session_owner_ == SessionOwner::kTracingController;
 }
 
@@ -129,7 +128,7 @@ base::trace_event::TraceConfig TraceStartupConfig::GetTraceConfig() const {
 
 int TraceStartupConfig::GetStartupDuration() const {
   DCHECK(IsEnabled() || IsUsingPerfettoOutput());
-  return startup_duration_;
+  return startup_duration_in_seconds_;
 }
 
 bool TraceStartupConfig::ShouldTraceToResultFile() const {
@@ -174,19 +173,21 @@ 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);
+    if (!startup_duration_str.empty() &&
+        !base::StringToInt(startup_duration_str, &startup_duration_in_seconds_)) {
+      DLOG(WARNING) << "Could not parse --" << switches::kTraceStartupDuration
+                    << "=" << startup_duration_str << " defaulting to 5 (secs)";
+      startup_duration_in_seconds_ = kDefaultStartupDurationInSeconds;
+    }
+  }
+
   if (!command_line->HasSwitch(switches::kTraceStartup))
     return false;
 
-  std::string startup_duration_str =
-      command_line->GetSwitchValueASCII(switches::kTraceStartupDuration);
-  startup_duration_ = kDefaultStartupDuration;
-  if (!startup_duration_str.empty() &&
-      !base::StringToInt(startup_duration_str, &startup_duration_)) {
-    DLOG(WARNING) << "Could not parse --" << switches::kTraceStartupDuration
-                  << "=" << startup_duration_str << " defaulting to 5 (secs)";
-    startup_duration_ = kDefaultStartupDuration;
-  }
-
   trace_config_ = base::trace_event::TraceConfig(
       command_line->GetSwitchValueASCII(switches::kTraceStartup),
       command_line->GetSwitchValueASCII(switches::kTraceStartupRecordMode));
@@ -210,9 +211,6 @@ bool TraceStartupConfig::EnableFromConfigFile() {
 #endif
 
   if (trace_config_file.empty()) {
-    // If the trace config file path is not specified, trace Chrome with the
-    // default configuration for 5 sec.
-    startup_duration_ = kDefaultStartupDuration;
     is_enabled_ = true;
     should_trace_to_result_file_ = true;
     DLOG(WARNING) << "Use default trace config.";
@@ -257,7 +255,7 @@ bool TraceStartupConfig::EnableFromBackgroundTracing() {
   should_trace_to_result_file_ = false;
   // Set startup duration to 0 since background tracing config will configure
   // the durations later.
-  startup_duration_ = 0;
+  startup_duration_in_seconds_ = 0;
   return true;
 }
 
@@ -276,11 +274,11 @@ bool TraceStartupConfig::ParseTraceConfigFileContent(
 
   trace_config_ = base::trace_event::TraceConfig(*trace_config_dict);
 
-  if (!dict->GetInteger(kStartupDurationParam, &startup_duration_))
-    startup_duration_ = 0;
+  if (!dict->GetInteger(kStartupDurationParam, &startup_duration_in_seconds_))
+    startup_duration_in_seconds_ = 0;
 
-  if (startup_duration_ < 0)
-    startup_duration_ = 0;
+  if (startup_duration_in_seconds_ < 0)
+    startup_duration_in_seconds_ = 0;
 
   base::FilePath::StringType result_file_or_dir_str;
   if (dict->GetString(kResultFileParam, &result_file_or_dir_str))

components/tracing/common/trace_startup_config.h

@@ -147,6 +147,8 @@ class TRACING_EXPORT TraceStartupConfig {
   friend class content::CommandlineStartupTracingTest;
   friend class content::BackgroundStartupTracingTest;
 
+  constexpr static int kDefaultStartupDurationInSeconds = 5;
+
   TraceStartupConfig();
   ~TraceStartupConfig();
 
@@ -161,7 +163,7 @@ class TRACING_EXPORT TraceStartupConfig {
   bool is_enabled_ = false;
   bool enable_background_tracing_for_testing_ = false;
   base::trace_event::TraceConfig trace_config_;
-  int startup_duration_ = 0;
+  int startup_duration_in_seconds_ = kDefaultStartupDurationInSeconds;
   bool should_trace_to_result_file_ = false;
   base::FilePath result_file_;
   bool finished_writing_to_file_ = false;

content/browser/tracing/startup_tracing_browsertest.cc

@@ -164,7 +164,7 @@ class BackgroundStartupTracingTest : public ContentBrowserTest {
     auto* startup_config = tracing::TraceStartupConfig::GetInstance();
     startup_config->enable_background_tracing_for_testing_ = true;
     startup_config->EnableFromBackgroundTracing();
-    startup_config->startup_duration_ = 3;
+    startup_config->startup_duration_in_seconds_ = 3;
     tracing::EnableStartupTracingIfNeeded();
     command_line->AppendSwitchASCII(switches::kPerfettoOutputFile,
                                     temp_file_path_.AsUTF8Unsafe());