[Ozone-Dri] Decouple the IO helper thread from DriWrapper

ui/ozone/platform/dri/ozone_platform_gbm.cc

Index: ui/ozone/platform/dri/ozone_platform_gbm.cc
diff --git a/ui/ozone/platform/dri/ozone_platform_gbm.cc b/ui/ozone/platform/dri/ozone_platform_gbm.cc
index 20f9450133b9f9acb03ec5ec33220795ca6006ab..396f1b9cf150049bac866957ecfcbe87c96ca4cf 100644
--- a/ui/ozone/platform/dri/ozone_platform_gbm.cc
+++ b/ui/ozone/platform/dri/ozone_platform_gbm.cc
@@ -26,6 +26,7 @@
 #include "ui/ozone/platform/dri/gbm_surface.h"
 #include "ui/ozone/platform/dri/gbm_surface_factory.h"
 #include "ui/ozone/platform/dri/gbm_wrapper.h"
+#include "ui/ozone/platform/dri/io_helper_thread.h"
 #include "ui/ozone/platform/dri/native_display_delegate_dri.h"
 #include "ui/ozone/platform/dri/native_display_delegate_proxy.h"
 #include "ui/ozone/platform/dri/scanout_buffer.h"
@@ -148,8 +149,12 @@ class OzonePlatformGbm : public OzonePlatform {
 
   void InitializeGPU() override {
     gl_api_loader_.reset(new GlApiLoader());
+    if (use_surfaceless_)
+      io_helper_thread_.reset(new IOHelperThread());
+
     // Async page flips are supported only on surfaceless mode.
-    gbm_.reset(new GbmWrapper(kDefaultGraphicsCardPath, !use_surfaceless_));
+    gbm_.reset(
+        new GbmWrapper(kDefaultGraphicsCardPath, io_helper_thread_.get()));
     gbm_->Initialize();
     buffer_generator_.reset(new GbmBufferGenerator());
     screen_manager_.reset(
@@ -171,6 +176,7 @@ class OzonePlatformGbm : public OzonePlatform {
  private:
   bool use_surfaceless_;
   scoped_ptr<GlApiLoader> gl_api_loader_;
+  scoped_ptr<IOHelperThread> io_helper_thread_;
   scoped_ptr<GbmWrapper> gbm_;
   scoped_ptr<GbmBufferGenerator> buffer_generator_;
   scoped_ptr<ScreenManager> screen_manager_;