Switch DRM platform to using a separate thread

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

Index: ui/ozone/platform/drm/gpu/drm_gpu_platform_support.h
diff --git a/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.h b/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.h
index 21caf35e6550877b29c2cadb9133d99aad7ba639..e3676aeec3cfb48f23a937f1634a9074f3c5659f 100644
--- a/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.h
+++ b/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.h
@@ -5,18 +5,16 @@
 #ifndef UI_OZONE_PLATFORM_DRM_GPU_DRM_GPU_PLATFORM_SUPPORT_H_
 #define UI_OZONE_PLATFORM_DRM_GPU_DRM_GPU_PLATFORM_SUPPORT_H_
 
-#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
-#include "ipc/message_filter.h"
+#include "base/memory/weak_ptr.h"
 #include "ui/display/types/display_constants.h"
 #include "ui/gfx/native_widget_types.h"
-#include "ui/ozone/public/gpu_platform_support.h"
 
 class SkBitmap;
 
 namespace base {
 class FilePath;
-class SingleThreadTaskRunner;
 struct FileDescriptor;
 }
 
@@ -25,34 +23,36 @@ class Point;
 class Rect;
 }
 
+namespace IPC {
+class Message;
+class Sender;
+}
+
 namespace ui {
 
 class DrmDeviceManager;
 class DrmGpuDisplayManager;
-class DrmSurfaceFactory;
-class DrmWindow;
 class ScreenManager;
 class ScanoutBufferGenerator;
 
 struct DisplayMode_Params;
-struct DisplaySnapshot_Params;
 struct OverlayCheck_Params;
 struct GammaRampRGBEntry;
 
-class DrmGpuPlatformSupport : public GpuPlatformSupport {
+class DrmGpuPlatformSupport
+    : public base::SupportsWeakPtr<DrmGpuPlatformSupport> {
  public:
+  typedef base::Callback<void(IPC::Message*)> IPCSender;
+
   DrmGpuPlatformSupport(DrmDeviceManager* drm_device_manager,
                         ScreenManager* screen_manager,
                         ScanoutBufferGenerator* buffer_generator,
                         scoped_ptr<DrmGpuDisplayManager> display_manager);
-  ~DrmGpuPlatformSupport() override;
+  ~DrmGpuPlatformSupport();
 
-  // GpuPlatformSupport:
-  void OnChannelEstablished(IPC::Sender* sender) override;
-  IPC::MessageFilter* GetMessageFilter() override;
+  void RegisterSender(const IPCSender& sender);
 
-  // IPC::Listener:
-  bool OnMessageReceived(const IPC::Message& message) override;
+  bool OnMessageReceived(const IPC::Message& message);
 
  private:
   void OnCreateWindow(gfx::AcceleratedWidget widget);
@@ -83,16 +83,12 @@ class DrmGpuPlatformSupport : public GpuPlatformSupport {
   void OnSetHDCPState(int64_t display_id, HDCPState state);
   void OnSetGammaRamp(int64_t id, const std::vector<GammaRampRGBEntry>& lut);
 
-  void SetIOTaskRunner(
-      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
-
-  IPC::Sender* sender_ = nullptr;             // Not owned.
-  DrmDeviceManager* drm_device_manager_;  // Not owned.
-  ScreenManager* screen_manager_;         // Not owned.
+  DrmDeviceManager* drm_device_manager_;      // Not owned.
+  ScreenManager* screen_manager_;             // Not owned.
   ScanoutBufferGenerator* buffer_generator_;  // Not owned.
 
   scoped_ptr<DrmGpuDisplayManager> display_manager_;
-  scoped_refptr<IPC::MessageFilter> filter_;
+  IPCSender sender_;
 };
 
 }  // namespace ui