Implement sampling profiler (chromium side change)

content/browser/tracing/tracing_controller_impl.cc

Index: content/browser/tracing/tracing_controller_impl.cc
diff --git a/content/browser/tracing/tracing_controller_impl.cc b/content/browser/tracing/tracing_controller_impl.cc
index ead4cf24359b0ecc59d17b93a2aebcdb5cd5e291..8b4877eb95754f0af38c184627d01fdb32d02c9a 100644
--- a/content/browser/tracing/tracing_controller_impl.cc
+++ b/content/browser/tracing/tracing_controller_impl.cc
@@ -80,7 +80,7 @@ void TracingControllerImpl::ResultFile::OpenTask() {
 
 void TracingControllerImpl::ResultFile::WriteTask(
     const scoped_refptr<base::RefCountedString>& events_str_ptr) {
-  if (!file_)
+  if (!file_ || !events_str_ptr->data().size())
     return;
 
   // If there is already a result in the file, then put a commma
@@ -173,7 +173,9 @@ bool TracingControllerImpl::EnableRecording(
   // TODO(haraken): How to handle ENABLE_SYSTRACE?
 
   TraceLog::GetInstance()->SetEnabled(
-      base::debug::CategoryFilter(category_filter), trace_options);
+      base::debug::CategoryFilter(category_filter),
+      base::debug::TraceLog::RECORDING_MODE,
+      trace_options);
   is_recording_ = true;
 
   // Notify all child processes.
@@ -247,10 +249,11 @@ bool TracingControllerImpl::EnableMonitoring(
 
   int monitoring_tracing_options = 0;
   if (options & ENABLE_SAMPLING)
-    monitoring_tracing_options |= base::debug::TraceLog::MONITOR_SAMPLING;
+    monitoring_tracing_options |= base::debug::TraceLog::ENABLE_SAMPLING;
 
   TraceLog::GetInstance()->SetEnabled(
       base::debug::CategoryFilter(category_filter),
+      base::debug::TraceLog::MONITORING_MODE,
       static_cast<TraceLog::Options>(monitoring_tracing_options));
 
   // Notify all child processes.
@@ -420,7 +423,7 @@ void TracingControllerImpl::AddTraceMessageFilter(
     trace_message_filter->SendSetWatchEvent(watch_category_name_,
                                             watch_event_name_);
   }
-  if (can_disable_recording()) {
+  if (can_disable_recording() || can_disable_monitoring()) {
     trace_message_filter->SendBeginTracing(
         TraceLog::GetInstance()->GetCurrentCategoryFilter().ToString(),
         TraceLog::GetInstance()->trace_options());