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

ui/ozone/platform/dri/dri_wrapper.h

Index: ui/ozone/platform/dri/dri_wrapper.h
diff --git a/ui/ozone/platform/dri/dri_wrapper.h b/ui/ozone/platform/dri/dri_wrapper.h
index 0dfa86691363cdc21a7fca32d84cc669ed4ef790..9a342fc5d180c22b9b1359e096f601973bca75c9 100644
--- a/ui/ozone/platform/dri/dri_wrapper.h
+++ b/ui/ozone/platform/dri/dri_wrapper.h
@@ -27,6 +27,7 @@ struct SkImageInfo;
 namespace ui {
 
 class HardwareDisplayPlaneManager;
+class DriHelperThread;
 
 // Wraps DRM calls into a nice interface. Used to provide different
 // implementations of the DRM calls. For the actual implementation the DRM API
@@ -37,7 +38,10 @@ class DriWrapper {
                               unsigned int /* seconds */,
                               unsigned int /* useconds */)> PageFlipCallback;
 
-  DriWrapper(const char* device_path, bool use_sync_flips);
+  // TODO(dnicoara) We should be passing a TaskRunner, however we cannot
+  // initialize the thread that early since the Ozone platform (and DriWrapper)
+  // is initializing before the sandbox.
+  DriWrapper(const char* device_path, DriHelperThread* helper_thread);
   virtual ~DriWrapper();
 
   // Open device.
@@ -163,9 +167,6 @@ class DriWrapper {
 
   scoped_ptr<HardwareDisplayPlaneManager> plane_manager_;
 
-  // If we need to block when performing page flips this is set to true.
-  bool use_sync_flips_;
-
  private:
   class IOWatcher;
 
@@ -175,7 +176,7 @@ class DriWrapper {
   // Helper thread to perform IO listener operations.
   // TODO(dnicoara) This should really be supported by the main thread.
   // Alternatively we should have a way to access the IO thread's task runner.
-  base::Thread io_thread_;
+  DriHelperThread* helper_thread_;
 
   // Watcher for |fd_| listening for page flip events.
   scoped_refptr<IOWatcher> watcher_;