Add granular file tracing.

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 3a235fe5bdaf803c7790dfdb12de1e554e952550..f063aa3f57e2f7deaec7c15b4cfa295d71f49c29 100644
--- a/content/browser/tracing/tracing_controller_impl.cc
+++ b/content/browser/tracing/tracing_controller_impl.cc
@@ -9,6 +9,7 @@
 #include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/trace_event/trace_event.h"
+#include "content/browser/tracing/file_tracing_provider_impl.h"
 #include "content/browser/tracing/trace_message_filter.h"
 #include "content/browser/tracing/tracing_ui.h"
 #include "content/common/child_process_messages.h"
@@ -57,6 +58,9 @@ TracingControllerImpl::TracingControllerImpl()
       is_recording_(TraceLog::GetInstance()->IsEnabled()),
       is_monitoring_(false) {
   base::trace_event::MemoryDumpManager::GetInstance()->SetDelegate(this);
+
+  // Deliberately leaked, like this class.
+  base::FileTracing::SetProvider(new FileTracingProviderImpl);
 }
 
 TracingControllerImpl::~TracingControllerImpl() {