Switch DRM platform to using a separate thread

ui/ozone/platform/drm/gpu/drm_device.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_OZONE_PLATFORM_DRM_GPU_DRM_DEVICE_H_
 #define UI_OZONE_PLATFORM_DRM_GPU_DRM_DEVICE_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 31 matching lines @@
  public:
   typedef base::Callback<void(unsigned int /* frame */,
                               unsigned int /* seconds */,
                               unsigned int /* useconds */)> PageFlipCallback;
 
   DrmDevice(const base::FilePath& device_path, base::File file);
 
   // Open device.
   virtual bool Initialize(bool use_atomic);
 
-  // |task_runner| will be used to asynchronously page flip.
-  virtual void InitializeTaskRunner(
-      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
-
   // Get the CRTC state. This is generally used to save state before using the
   // CRTC. When the user finishes using the CRTC, the user should restore the
   // CRTC to it's initial state. Use |SetCrtc| to restore the state.
   virtual ScopedDrmCrtcPtr GetCrtc(uint32_t crtc_id);
 
   // Used to configure CRTC with ID |crtc_id| to use the connector in
   // |connectors|. The CRTC will be configured with mode |mode| and will display
   // the framebuffer with ID |framebuffer|. Before being able to display the
   // framebuffer, it should be registered with the CRTC using |AddFramebuffer|.
   virtual bool SetCrtc(uint32_t crtc_id,
@@ skipping 121 matching lines @@
  private:
   class IOWatcher;
   class PageFlipManager;
 
   // Path to DRM device.
   const base::FilePath device_path_;
 
   // DRM device.
   base::File file_;
 
-  // Helper thread to perform IO listener operations.
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  scoped_ptr<PageFlipManager> page_flip_manager_;
 
   // Watcher for |fd_| listening for page flip events.
-  scoped_refptr<IOWatcher> watcher_;
-
-  scoped_refptr<PageFlipManager> page_flip_manager_;
+  scoped_ptr<IOWatcher> watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(DrmDevice);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRM_GPU_DRM_DEVICE_H_