Restore "Capture Skia trace events" (#2834)

sky/shell/shell.cc

diff --git a/sky/shell/shell.cc b/sky/shell/shell.cc
index b361283..37cdf9d 100644
--- a/sky/shell/shell.cc
+++ b/sky/shell/shell.cc
@@ -18,6 +18,7 @@
 #include "base/single_thread_task_runner.h"
 #include "base/trace_event/trace_event.h"
 #include "mojo/message_pump/message_pump_mojo.h"
+#include "skia/ext/event_tracer_impl.h"
 #include "sky/engine/core/script/dart_init.h"
 #include "sky/engine/public/platform/sky_settings.h"
 #include "sky/shell/diagnostic/diagnostic_server.h"
@@ -149,6 +150,11 @@
 
 void Shell::Init() {
   base::DiscardableMemoryAllocator::SetInstance(&g_discardable.Get());
+
+#ifndef FLUTTER_PRODUCT_MODE
+  InitSkiaEventTracer();
+#endif
+
   DCHECK(!g_shell);
   g_shell = new Shell();
   g_shell->ui_task_runner()->PostTask(FROM_HERE, base::Bind(&Engine::Init));

sky/shell/tracing_controller.cc

diff --git a/sky/shell/tracing_controller.cc b/sky/shell/tracing_controller.cc
index a511a25..fa9058f 100644
--- a/sky/shell/tracing_controller.cc
+++ b/sky/shell/tracing_controller.cc
@@ -178,7 +178,7 @@
 
 void TracingController::StartBaseTracing() {
   namespace TE = base::trace_event;
-  auto config = TE::TraceConfig("*", TE::RECORD_CONTINUOUSLY);
+  auto config = TE::TraceConfig("*,disabled-by-default-skia", TE::RECORD_CONTINUOUSLY);
 
   auto log = TE::TraceLog::GetInstance();