Record Chrome trace events in tcmalloc heap profiles

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index d95dbb594142047be0deb447367a014e2279b908..131be72f04416f39a689416d580bc4429a605421 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -474,6 +474,8 @@ void BrowserMainLoop::MainMessageLoopStart() {
     base::MessageLoop::current()->AddTaskObserver(memory_observer_.get());
   }
 
+  trace_system_controller_.reset(new base::debug::TraceSystemController(
+      base::MessageLoop::current()->message_loop_proxy()));
 #if defined(TCMALLOC_TRACE_MEMORY_SUPPORTED)
   trace_memory_controller_.reset(new base::debug::TraceMemoryController(
       base::MessageLoop::current()->message_loop_proxy(),
@@ -642,6 +644,7 @@ void BrowserMainLoop::ShutdownThreadsAndCleanUp() {
     parts_->PostMainMessageLoopRun();
 
   trace_memory_controller_.reset();
+  trace_system_controller_.reset();
 
 #if !defined(OS_IOS)
   // Destroying the GpuProcessHostUIShims on the UI thread posts a task to